x86 is on the way out and can't compete on power or performance. In the end RISC won, it just took a while to get there.
As things trend that direction AMD and Intel don't really have much to offer, they're competing on legacy tech.
With TSMC providing fabs for designs from anyone, the serious players don't need AMD or Intel. Apple has a massive lead here, but others watching this will follow it.
What exactly do you think is the fundamental limitation of x86? Most chips do lot and lots of crazy logic to go from instruction set to microcode, it's hard to imagine that the variable nature of x86 instructions are the limiting factor.
The "x86 tax" (if it exists, I guess) is usually estimated at somewhere on the order of 5% to 10% - which is a lot of money at scale but probably not enough for a total rethink.
There’s also the coordination problem with windows and third parties. Without vertical integration and tight OS support they’ll fall behind.
Something will have to give, but the future doesn’t look good.
It's like train companies thinking they shouldn't compete with cars because they're in the train business (without realizing they’re actually in the transportation business).
AMD is in the chip business, not the x86 business - and x86 just became a whole lot less relevant for the future.
Apple has the vertical integration to do it properly. Amazon and Microsoft have the server cloud computing to do it server side.
Without proper coordination from Microsoft, third party OEMs, and AMD they'll all fall behind on computing on end devices.
I think that's part of the reason AMD/Intel will be less relevant, the incentives and market moves don't look good for them.