Microsoft is not stupid, Microsoft has ported everything to ARMv8 already, both for the Snapdragon laptops and the servers (which they only use internally for now, but I hope Amazon's Graviton is pushing them in the ARM-public-cloud direction)
And by everything… I mean not just Windows, but even SQL Server now: https://twitter.com/ASGConf/status/1173163007733616641
Fwiw, the NT kernel was designed for portability from the ground up. During initial development they targeted x86 and the i680 and it has been ported to pretty much any CPU that had relevance over time. Itanium, Alpha, ARM and.... PowerPC. While that branch is probably not maintained currently it would be pretty easy for Microsoft to get that going again.
If you want to run Linux in the cloud, you've got a bunch of providers (Google, Amazon, Microsoft, etc)
Microsoft simply wants to be in that market, so they'll offer the same products their competition does. Anything they can do to make Linux better on Azure is considered a net gain for them
I think Intel has been too dominant for too long. They've gotten complacent and sloppy, as shown by microcode-level vulnerabilities like Spectre and Meltdown.
Also, I figure breaking Intel's dominance will further marginalize Microsoft. I still hold a grudge over how horrible an experience Windows 98 was.