Re: re: Redmond tells us they are looking at RISC-V to diversify their risk.
Apple have shown the way on how to migrate one arch to another. Rosetta in it's latest incarnations works very well indeed for X86-64 on ARM. Much better than the lagfest that was Rosetta for PPC to Intel.
It is not merely compatible but of comparable or better performance. In my limited sample size of comparing performance of Reason 11 running on an M1 Mac Pro with a 2013 intel mac pro.
Itanium tanked for, amongst other reasons, a failing of compilers to deliver on promises. Availability was never wide enough to rely on customers to roll their own tools to improve the platform. To say nothing of the hardware being a steaming brick. Intel had an ARM project around the time of the 486. The world wasn't ready for that, not in the face of Windows 3.1, and nor was emulation practicable on hardware of that time.
Rosetta in the more convoluted Windows space would be tougher than on Apple but certainly not impossible, and bypasses the recompile everything problem neatly; until the next version when your vendor will want to say they have re-engineered for it.
X86 has made drastic improvements of 40 years in terms of numbers of instructions complete per clock cycle. When talking about frequencies north of 3GHz; executing marginally more instructions per cycle makes an enormous difference; and so ARM represents a jump over what X86 can do. Moving arch is not as difficult as it once was, and the performance advantages cannot be ignored. Let's face it - once you have a working assembler, you are not far off a working C compiler; and then in turn you can build practically anything from that.
Programmers motivated to learn assemblers are rare; and perhaps even more so on hardware still in it's evolutionary / developmental stages. They are the difference between a platform becoming viable or not. Apple recognised this, and took advantage of what it had already done in the mobile space to realise it on desktop.
If Intel doesn't do it, someone else probably will. See Chromebook (for all it's foibles). Or AMD on X86-64 vs. Itanium.