alt Hacker News> If Itanium never happened, 64-bit x86 server chips would have done the same thing to MIPS, Alpha, PA-RISC, SPARC, PowerPC.
If AMD had launched amd64 server chips those vendors onboard we might have had a different 64-bit x86 market. And those vendors would have had a chance to succeed or fail on their own merits instead of due to dead end chip.
AMD did launch amd64 server chips. The first ones were Opteron, first (and only until Nehalem) x86 with ODMC, glueless multiprocessor up to 8-way (though that was a bit flakey, 4-way was decent), and first dual core. It destroyed Intel's CPUs in many measure of performance for server workloads.
Before Intel's decade of humiliation with their 10nm fiasco and before Zen, AMD had a hell of a time getting ISVs and IHVs on board in the server space with producing them, certifying them, etc.,. Which wasn't entirely irrational, Intel was much more mature in a lot of ways in their hardware and software stacks, they were a big company, perceived as less risky, etc.
So it's not too surprising that those companies didn't jump to Opteron. Some did consider it, mind you. Though AMD went through doldrums of their own after Opteron (with Core2/Nehalem-ish era) where they shat the bed with their cores and were pretty handily beaten by Intel for quite a long while until Zen came along -- so that is possibly some vindication for the risk adverse by not going all in on Opteron.