I'll take this point by point rather than trying to reply in one bulk comment. It seems simpler that way. This is going to be a fairly long post because when I get myself going I find it hard to stop writing. Sorry if this gets tl;dr.
It's a lot easier when you strip away most of the sponsorship nonsense.
For example, we don't have anything like the Capital One Cup, which I've learned is the Football League Cup. If we combined USL, NASL and MLS into a competition, that would be our equivalent of the FL Cup.
Very much so. If you read English forums, as opposed to just news sources, you may notice that we as a general rule do not refer to the sponsor. Pretty much...ever. In fact, many of us find the fact that these competitions need to have a sponsor tacked onto the name fairly galling and ever so slightly obnoxious. Indeed, for this reason, most of us assume that when Americans (or pretty much anyone else) refers to the "BPL" meaning "Barclays Premier League", that the American in question is actually calling it the "British Premier League", as we simply can't work out what the B is supposed to be for otherwise, and that raises a whole different kettle of fish - one this thread has already brought up. Some folk here wouldn't even know who the sponsor is, because we consciously try to ignore that they have them.
As a general rule, if you want to talk to English people about English competitions, do not mention the sponsor name.
I'm assuming the driving force behind all these competitions is dinero.
Actually, this is one major place where you'd be wrong. The driving force behind all of these competitions is tradition. Tradition is important in the UK in a way you simply can't compare to most other countries in the world. Times are slowly changing, but to many people, things - pretty much anything under the right circumstances - can become sacrosanct if they are rooted in tradition, especially if they are rooted in the knowledge that the tradition goes back further than anyone alive who can remember a time before it happened. When people call for traditions to be scrapped, or even altered, there tends to be a massive backlash, and often that backlash is not so much rooted in the fact that people do not think the change is a good thing but just that the idea of changing something which has always been the same goes against the grain in a way people just can't handle.
Take, for example, the propositions a couple of years ago to allow PL sides to operate B-teams inside the actual league structure, where they have always priorly had a (very non-competitive) "reserve league" which was nothing more than a rehabilitation league for injured first team players plus a handful of youths. Everyone knew this system wasn't working. Everyone hated the reserve leagues and everyone agreed that they had to go. However, professional teams have never had B-teams in the actual league pyramid. About 50-100 years ago some clubs did run them in lower leagues where they played competitive games against amateur sides, but that was before those lower leagues became connected to the Football League by the promotion/relegation system. The PL is broadly in favour of B-teams, but the Football League and the Conference (I abhor the new "National League" name, makes it sound like a Nazi rally) refuse to let them in because it threatens their traditional position in the order of precedence.
In fairness, under the proposed rules they would probably get a fairly bum deal, but even if a compromise was offered which made it financially lucrative for FL clubs it would still be unpopular because it would mean allowing an upstart B-team to usurp their position and get in the way of their dreams of eventually reaching the PL. No club is willing to accept that, so B-teams will never happen - not in a serious way, anyway.
There have been various murmurs recently about getting rid of certain competitions, or at least reducing them. Some competitions, especially in the first rounds, are not financially favourable and some clubs actually spend more than they earn in winnings on travel costs. Some people also suggest removing PL sides from the League Cup and replacing it with a PL Cup to reduce the number of games that have to be played and to make those games more important to the clubs involved. You want to know why that will never happen? Because it just doesn't fit the way English football works, that's why.
Or another example - most European leagues have a winter break of 2-4 weeks over Christmas. This lets players stay home and see their families, and also when you consider some teams play more than 60 games a season, it's important for fitness and health. However, in England we have always had a tradition of every single team playing a game on Boxing Day (26th December - another tradition) and one on New Year's Day. This is the only reason we won't allow winter breaks, and we all know it is hurting the league but it's something that society just won't allow to stop happening. Most clubs even make their players do a day's training on Christmas Day, just to make sure they are ready for the Boxing Day game, because it's that important to us.
To put this into perspective as relates to your question - the youngest competitions that any professional side compete in are the Football League Trophy (1983) and the Football League Cup (1960). The Football League goes back to 1888. The FA Cup goes back to 1871. The Premier League is an exception to the rule - it only came into existence because the top tier of English clubs in 1991-92 decided they were getting cheated out of TV money by the Football League. In terms of how the PL is organised, it remains essentially the exact same competition as it was before, it just has a lot more money and independence now. Most people would not make a distinction between a team's overall league wins and their PL wins, though, except in the context of modern performance compared with historic.
Recently, while perusing the BPL website, I noticed that there's an U23 (21?) Premier League.
How many different leagues fall under the Premier League umbrella and how much attention is paid to them
Slightly hard to answer. The U21 PL competition (U23 is an age bracket that doesn't really exist in the British consciousness - to us, once you are too old for U21 you are a senior player) is a recent invention as part of the drive to get rid of reserve football and replace it with something that's better for kids. It carries the PL name, but it's not exclusive to the PL - it's open to the academy sides of any PL or FL club, so long as they meet certain criteria on the quality of their academy facilities. In fact, "Under-21 Premier League" is only its sponsor name. It's technically called the Professional Development League, and the U21 PL is just the first of three tiers of it. In this instance, the PL name is used more for marketing than because of a direct connection.
As for other competitions - there is an U18 PL, but that is just the junior competition under the PDL, and it operates in the same way. There is also a U21 PL Cup, which again is linked to the PDL. There is the Premier League Asia Trophy, which is nothing more than a biennial friendly competition for three PL teams (generally one top six, one mid-table and one relegation-battler) and one Asian club, always played in Asia and basically there to generate Asian interest in the league.
Finally, there is the Premier League International Cup, which is an English-centric U21 version of the Champions League, with as many English teams as European sides. It's entirely invitation only, even for the English clubs (only PL clubs are eligible, unlike the PDL) and basically exists to give youth players experience of competitive European matches. With the creation of the UEFA Youth League, they may scrap this competition soon.
With the exception of the Premier League Asia Trophy (which was started in 2003) all of the above only came into existence in the last 3-4 years. They're pretty much all a reaction to the FA insisting that standards of youth training must drastically improve, and are all a response to the idea that the best way to do this is by making youth football more competitive.
The latest iteration of NASL is a breakaway faction from USL. Without getting into the politics of it, NASL broke away from USL and after a cooling off period, NASL became Division 2 in the US pyramid and USL Division 3.
I gather FA is separate from the Football League.
The Football Association is analagous to the US Soccer Federation.
The Football League seems to be analogous to United Soccer Leagues which is the parent of USL.
That's basically all accurate.
