Marvel has been getting slammed lately for a comment in an interview with ICv2 by David Gabriel - he said, "What we heard was that people didn't want any more diversity. They didn't want female characters out there. That's what we heard, whether we believe that or not. I don't know that that's really true, but that's what we saw in sales."
Those comments were "walked back" almost immediately - Marvel certainly doesn't want to be seen as anti-diversity, of course - but once the topic was raised, it was impossible to stuff it back in Pandora's Box.
It's certainly possible that it's true - that the new "diverse" versions of their heroes aren't selling as well as the original versions.
That would be surprising. Generally speaking, and "new and different" take on a character will spark at least a temporary spike in sales. The female Thor, for example, seems to be selling in higher numbers than the most recent "classic Thor" title.
These "revamp the heroes' waves seem to come along every couple of decades - certainly they've replaced Iron Man before (with War Machine), along with Thor (Thunderstrike), Captain America (Nomad / The Captain), and Spider-Man (Scarlet Spider).
But if it's a cause for lost sales, it's just one of many.
There are so many reasons that are more likely to blame, including: high prices, the over-saturation of the market with marginal titles, event fatigue, bad writing, less than stellar artwork, and yes, character assassination.
Diversity is actually one of the few good things they're doing these days, though I wish they could do it without tearing down the original heroes. Ms. Marvel and Squirrel Girl are good examples of re-imagining existing or unused character concepts into new and exciting properties.
It's just a matter of time until the original version of the heroes return - in fact, an upcoming event is called "Generations" (or somesuch), and it'll focus on the (returning) original and newer characters with familiar names, so perhaps this is all just laying the groundwork for the next big thing.
If Marvel suddenly (and foolishly) put me in charge, what would I do to correct the course? Well, I'd try to reduce prices. Four bucks for a comic book is a step too far for many readers. DC's done well by keeping the line at $3, but word is that they'll soon have to give in and raise their prices, too.
I'd put the focus on the writing again - I think that's what made Marvel stand out for a long time. With the loss of Ed Brubaker and Jonathan Hickman, the writing staff seems a bit thin (with only Brian Michael Bendis standing out from the crowd of mostly unknown writers). Hire some reliable pros (Dixon, Stern, Morrison, Ellis) and let them fly.
Keep the focus on great art.
Reduce the size of the line, and whittle down the families - we don't need a half-dozen X-titles, Spider-books or Avenger spinoffs.
Put a one-year moratorium on Event books. If you have a good story to tell, use it in one of the titles - or make it a summer Annual.
Bring back the classic heroes, use them together in a team, and allow them to be friends.
Watch the movies, and go forth and do likewise.
And in the name of all that's Stanley, bring back the Fantastic Four! It just isn't Marvel without the first family.