I'll try to state things that I didn't read yet in this post (if I overlooked it, oops)
Microsoft: They introduced a paradigm of patches, incomplete releases etc. Back in the good old days, there was no such thing as a FIRMWARE update, and games worked fully upon release - because if they didn't, they didn't sell and someone got fired.
Sony: Because in their giant pissing contest with Microsoft, they embraced all of the things MS did (above) and more.
Nintendo: (Tough to say one that hasn't been said already so I'll say...) Overly complacent with hardware success. Needed to be pushing massive software along with it to deliver a killing blow - and line their pockets. Case in point, they should be USING this massive income to hire and create new studios so that the Nintendo name competes (if not dominates) in every genre.










