Around the time I was born, Microsoft couldn't help but brag about how "portable" Windows NT 3.x was. They claimed that they would continue adding support for more processor chips as they became available. I think NT 3.5 supported PowerPC before the Macintosh systems could, although support was dropped with 3.5.1.
I think there's a reason why even the NT versions of Windows have been so heavily tied to Intel ever since. I don't think a Windows program could run on a specific processor, unless that program was compiled for said processor. That said, there was no incentive to buy eg a MIPS machine just ro run Windows when an equivilent Intel chip could run more programs.
That said, it seems like Microsoft has forgotten about their past lessons, and gone full circle. Gee, I wonder what could go wrong?