Honestly, I think it doesn't.
Because, I
LOVE X-Men, Fantastic Four, Cap, etc.
Yet you know what? I don't really give a damn about any of their current ongoings (except for Cap

).
At a certain point, the continuity does become suffocating. Such is the problem with X-Men.
Often Marvel abandons the campier elements that make their characters fun, in favor of a more mature level of drama. Such is the problem with Fantastic Four.
And why do I read Cap? Because Brubaker took the character and made it accessible. Did what DC is doing with half of their books and took on a totally fresh start, without really abandoning any continuity.
And I used to have some appreciation for Spider-Man. But the ludicrousness of One More Day ended my run of reading his title.
I'm not trying to bash Marvel. Not at all. But despite their missteps, DC has managed to keep my engaged in their characters - characters I don't even like as much as a lot of Marvel's - for a much more prolonged period of time than Marvel. And I do thing it somewhat has to do with how DC treats it's continuity as apposed to Marvel.