I don't disagree with your comment but I think “nerds in bedrooms” is possibly what works for tuning a particular open source project. GCC and other popular open source projects should have been a room full of Intel engineers because it's a hard problem and their revenue from their proprietary compiler & libraries was a tiny rounding error of the amount they spent building Itanium.

Back when I supported computational scientists, the total cost of the servers + compilers was so steep that even if everything had worked as well as the Itanium salespeople promised it would have needed to be many times faster to be worth the hassle of changing toolchains, especially since you had to pay up front for the hope that with a fair amount of work you'd at least hit the point of breaking even.