Agreed. The only reason I can think of for AMD to set up an alternative instruction set would be a sudden rise in competition from other players. If big advances are made in the RISC-V space that make the architecture a cost effective alternative to amd64 (including the cost of porting software to RISC-V) then I can see them setting themselves up to allow running software on both platforms at native speeds.
I don't think AMD is currently limited by their instruction set. Even if they are, there may be an argument to move to ARM instead of RISC-V to take advantage of the software already ported because of Apple's transition and the Graviton chips. Windows already runs on ARM but hasn't been announced to run on RISC-V, after all.
>would be a sudden rise in competition from other players.
This is exactly what I see happening. AMD will have to move to RISC-V to stay competitive, and x86 acceleration is a compelling feature they can offer.
>Windows already runs on ARM but hasn't been announced to run on RISC-V, after all.
I doubt this one will be an issue for long. During last summit, in talks by the RISC-V foundation itself (specifically, the technical ones about ongoing ISA work), Windows was mentioned a few times as the reasoning for some new specifications.
This strongly implies Microsoft is working on Windows for RISC-V, even if Microsoft themselves haven't said a word about it.
I don't think AMD is currently limited by their instruction set. Even if they are, there may be an argument to move to ARM instead of RISC-V to take advantage of the software already ported because of Apple's transition and the Graviton chips. Windows already runs on ARM but hasn't been announced to run on RISC-V, after all.