What happens when you are no longer the darling. And PMs need to ship something new to get noticed, so they screw it all up
I read all the Windows 8 development blogs, and everything they wrote about seemed absolutely justified. Then you actually use the thing and it was a nightmare.
Same with their approach to hardware, the Duke Xbox controller tested really well, but then someone with daintier hands went to use it and uh actually its great for like 15% of the user base.