It is until it isn't, but I think this is the same trap as not training up junior engineers. The consumer market is often where future engineers and professionals first interact with technology, being exposed to Windows early and being able to use it at school and at home have always been major drivers of adoption at work.
Linux is another perfect example - devs who wanted a unix-ish system landed on it early in their own work and education (partly due to the BSD licensing stuff too) - and over time it became one of the most commonly used server operating systems.
I think this is Microsoft optimizing for predictable growth, just like everyone else is doing right now, but this is shortsighted and ultimately a defensive posture, not one suited for the future.