I wouldn't say PG is the first to call it. Joel Spolsky wrote an article with same jist a few years back (http://joelonsoftware.com/articles/APIWar.html), and I'm sure less known authors have been calling it before that. It's different when a big name with reputation on the line calls it, but Microsoft's being "dead" has been an open secret for a while.

I'm guessing I fall into this crowd: "The other half, the younger half, will complain that this is old news."