> I am convinced that the decay is often very slow. There are signs of impending failure and it frequently drags out for many, many years.

When Jobs contacted Otellini about having Intel fab an ARM chip for them and Otellini said no... That's probably about the time their fate was sealed. And that would've been around 2006. Yes, there were plenty of signs prior to that. For example: AMD needed a lot less engineers to spin a new processor rev than Intel did and AFAIK that's still the case.