Well, that certainly explains Microsoft's noncomittal stance on M1 support (even inside VMs).
I tend to doubt Microsoft wants an exclusive contract in the long run. The relationship between Microsoft and Intel has always been a mix of needing each other and hating each other. They're both trying to extract as much profit out of each PC sold as they can, which naturally creates conflicts. There's a reason why Microsoft was willing to port Windows NT to a raft of different CPU architectures back in the 1990s.
If they play their cards right, they can help create a world where Intel x86 hegemony fades away and is replaced by at least two viable Arm chipmakers, preferably three or more. This just wasn't possible with x86 due to the patent encumbrance.