Well if ARM laptops more power efficient, cheaper, faster which makes consumer choose it (either by going to iMac or installing linux) Microsoft might lose market share. It's also a great excuse to get new eye balls on legacy code and fix all king of issues

On another note: Windows have (by default) tons of legacy to support a lot of different hardware Am I wrong to assume that that most drivers on ARM cpu running through virtualization? Does Microsoft actually build them or get them from partners to install on the system