The issue I'd have is that there are shit load of classic characters that can't carry their own title either, so I don't the percentages are THAT skewed. Today we still deal with multiples of the ones that can - Batman family, Avengers, Mutant books etc, etc
I'd add Jessica Jones who apparently is getting a tv show. Sentry (who I thought was whack but certainly got a lot of air time).
Lots of thankless "suporters" though in The Hood, Phyla-Vell, Amon Sur, Black Alice, Skaar, people Like Bane in Birds of Prey.
Sure, it's SUPERHARD to make something that's a flagship, which is why a bunch of haters should lick Liefeld balls for Deadpool and Cable, because that's about as close as we've got and they're both the shit. It's arguable that Deadpool is the most significant comic book character creation since the 70s from a pure
what people actually like level
in comics books.