That's a long complicated answer that could go on for days as basically I'm into the EPL for incidental historical reasons. In the "olden" days that was all you could watch, for one, and then only a few games per weekend at that. And after the two EPL matches on Fox Soccer Channel you might get one Bundesliga but only if you were lucky. So I'd watch because I loved soccer, it was finally on TV during what used to be cartoon time, and it was pretty good. It took another few years and a random bit said by Rick Wakeman at a concert on Long Island before I started watching Man City more than the other teams.
So in a sense you're asking me for sound logical reasons why I watch the Premier League over other leagues and there really aren't any in particular. It's like asking why I'm a Mets fan rather than a Yankee fan. There's no particular reason, not really. I was two when the Mets started, so they were the lovable bums that captivated the whole city as I was growing up (although Mickey Mantle was one of my heroes as well, even though he was nearing the end of his career).
Anyway, I'm only on my first cup of coffee and am rambling a bit. Bottom line is that I do watch other leagues but I'm a *fan* of the EPL. The top EPL teams are excellent, and the bottom ones are, well, perhaps not so much. And I'm OK with that.