The important products (Photoshop, Illustrator, InDesign) were mature about ten years ago, and there's not much they could have done to improve them, aside from porting them to newer OSes and adding minor features. So there was a push to use their resources in some other way, which has obviously been to build platforms. The trouble with this is that Adobe is awful at it! They moved far away from what they were competent at, ruining their products along the way. Think about the terrible things Adobe has done to their products in the last decade:
* Acrobat reader is a ridiculously slow and bloated product. Preview.app is much faster and nicer-looking. I uninstall Acrobat whenever I can, and tell other people to do the same.
* Their creative suite has a ridiculously slow installer. Just let us drag the app to the Applications folder and leave things alone!
* They don't obey user interface guidelines (they never really did), but what they come up with now is almost always worse. (It wasn't always that way - the vertical toolbar was beautiful.) They really didn't need to add that crappy horizontal bar thing to Photoshop and Illustrator.
What should they do? Sell to Apple at a firesale price (which will seem really, really high after Adobe craters over the next five years). They should then get rid of everyone that manages all of this redundant platform-building bullshit (this would save Acrobat on Windows by making it decent - but then again, I'm not sure that Windows will be a major consumer platform in five years), and focus on building the beautiful creative tools that made their company great once. While there's a lot of work left to do to make Photoshop and Illustrator take advantage of the multitouch technologies that are coming in future Macs, we may rest assured that Adobe's present management will find a way to fuck it up.