[cm2187]

But I presume dropping support just means not being able to use the latest features.

Even a very old system image of windows 7 will run on the very latest skylake. It doesn't need the very latest updates. I doubt they will create a kill switch in a windows update that refuses to boot if the system detects a too modern CPU.

[Laforet]

They can refuse to provide a signed driver for the platform, but like you said it is unclear how far they will go.

Still better than Chrome endig support for Windows Vista this upcoming April...