Here's the thing. Everything you said is true, but I think you're not looking in the same direction I am. The problem with getting the great players to come here is not whether they can get the money their looking for in their time on an MLS team. The real problem is that most of the *other* players on their team are only getting paid $60,000 or so.
that's not even close to true.
Further, even if it were, if you're making only $60k, it's probably a good indicator you should give it up if you're over 23/24 (at which age that's still a decent to good wage relative to real world)
Even Jeb Brovsky made $70k his first year in the league when his stated salary was like $36k.
As a final point, why do folks propagate this misinformation? MLS pay is fine. What we're really talking about is paying shit roster-filler players, and I don't care about that nor see it as an issue. More money is conitunually being spent on deserving talents, so much so that MLS is one of the better paying leagues in the world.