Far too late for that. Does anyone seriously think ARM isn't going to obliterate x86 in the next 10-20 years?
Mature gallery of software to be ported from TSO to weak memory model is a soft moat. So is avx/simd mature dominance vs neon/sve. x86/64 is a duopoly and a stable target vs fragmented landscape of ARM. ARM's whole spiel is performance per watt, scale out type of thing vs scale up. In that sense the market has kind of already moved. With ARM if you start pushing for sustained high throughput, high performance, 5Ghz+ envelope, all the advantages are gone in favor of x86 so far.
What might be interesting is if let's say AMD adds an ARM frontend decoder to Zen. In one of Jim Keller's interviews that was shared here, he said it wouldn't be that big of a deal to make such a CPU for it to be an ARM decoding one. That'd be interesting to see.
Laptops. Apple already owned the high margin laptop market before they switched to ARM. With phones, tablets, laptops above 1k, and all the other doodads all running ARM, it's not that x86 will simply disappear. Of course not. But the investments simply aren't comparable anymore with ARM being an order of magnitude more common. x86 is very slowly losing steam, with their chips generally behind in terms of performance per watt. And it's not because of any specific problem or mistake. It's just that it no longer makes economic sense.
Obliterating x86 in that time would take quite a lot more than what the ARM trajectory is now. It's had 40 years to try by now and the technical advantage window (power efficieny advantage) has closed.
I was thinking more like if it falls to 10% of desktop/laptop/server market share, which is still waaaaaay more then the nearly-dead architectures you listed.
Things that have < 10% market share
- macOS
- all car manufacturers except Toyota
Things that history considers obliterated:
- The city of Pompeii
- districts of Hiroshima within the bomb's blast radius
Lunar Lake shows that x86 is capable of getting that energy efficiency
Panther Lake that will be released in around 30 days is expected to show significant improvement over Lunar Lake
So... why switch to ARM if you will get similar perf/energy eff?
So this is kind of a useless question, because in such a timespan anything can happen. 20 years ago computers had somewhere around 512MB of RAM and a single core and had a CRT on desk.
I like RISC-V (it's my job and I'm very involved in the community) but even now it isn't ready for laptops/desktop class applications. RVA23 is really the first profile that comes close and that was only ratified very recently. But beyond that there are a load of other things that are very much work in progress around the periphery that you need on a laptop. ACPI, UEFI, etc. If you know RISC-V, what does mconfigptr point to? Nothing yet!
Anyway the question was why would anyone switch from one proprietary ISA to another, as if nobody would - despite the very obvious proof that yes they absolutely would.