Apple is a bunch of control freaks. But they don't make much money from content; the overwhelming majority of their business is hardware sales.
Somewhere north of $14bn out of the $16bn in revenues from the last quarter is just hardware; the entire iTunes store, including apps and music and books, is around $1bn.
Maybe they'll go DRM-free on self-published books if they see an advantage. It's largely irrelevant though, since Apple doesn't care
whose ebooks you read, so long as you read it on an iPad or iPhone. In which case, you can just download the Kindle software, download your book and you're all set.