That's not entirely accurate. I blame high turnover. When no engineer is left to fight for their pet causes, AOL and Microsoft happen. Hell I attribute MS' decline more to turnover from very key players (one could out Bill Gates himself in this camp) more than any other metric. Having been at a very small shop to see this first hand, I notice it everywhere. Places don't bother to get new developers to really care enough to take ownership anymore. Its a burden they hope magically happens and never does.
The engineers step back, the marketers take over. Seems to be unavoidable for any economically successful company.