That's a pretty shocking pie chart. This industry (perhaps like all industries) always goes to far with a trend and pursues a strategy until it kills what it started. Meaning, a variant, a foil cover, a facsimile, a crossover, etc., these can all be neat and cool when used sparingly, but when books are only being printed to sell a variant, what are we doing? Just sell limited print run posters.
Some might say that the variant game is only thing keeping the industry alive, but that's short sighted. Words and pictures being used together to tell a compelling story is what should be driving the industry. If you can't do that, then maybe you don't need to be publishing.
Is there any "data" on how variants affect long-term collectability of a title? It completely turns me off from trying to have a run because it is impossible to own them all. I know I was working on a complete CGC 9.8 of Invincible, but all these post-story, convention variants have killed my interest in that pursuit.