[disclosure, MS employee]
With the absence of telemetry, how do you know Linux is doing just fine? (specifically in the desktop world, not server world).
Microsoft has an interest in knowing how well Windows is doing, and Windows has lived in a world both with and without telemetry. It was way, way harder to gauge success prior to telemetry, and it was also much more frustrating for the user to communicate their problems. I don't think Windows could have stayed in the pre-telemetry engineering world and maintained its position as a competitive desktop OS.
I ask this mostly out of ignorance, I've got experience using Linux, but I really don't know what the dev-loop is like for active engineers.