Judging from the Photoshop thread (1). People has a lot of tolerance to abuse, and will allow themselves to obvious mistreatment for many years before finally figuring they deserve better, and giving up.

(1) http://news.ycombinator.com/item?id=4031595

They'd have to get fed up enough to move to a non-Apple ecosystem, and given how much the typical iOS/Mac dev loves Apple products, that seems unlikely unless a new player storms onto the market and finally delivers serious competition. Abuse like this will, at most, just make devs grumble more about how unkind Apple is; they're not going to stop making Apple rich anytime soon.

It's much less of an issue for the average developer than the fact that it's getting to be very, very hard to make any real money in the app store.

To quote from the article:

I really believe that the App Store is become more and more like an Android market – meaning 99% crap!

What is good and innovative about stealing Apple's private encryption key ?

First, as far as I'm aware, there's no allegation that either this developer or Rogue Amoeba was responsible for extracting and publishing the key in the first place.

Second, I think the point is that some developers did good and innovative things with the key. By itself, I'd call extracting and publishing the key a mundane technical challenge, nothing more.