(Short) story time!

Windows on ARM was a solo pet project of a high level engineer at Microsoft!

There are some engineers who are so valuable that letting them spend non-trivial amounts of time on whatever they want is a very good use of company resources.

Sometimes just not letting the competition have them is valuable!

I've worked with a few 10x-20x engineers, if someone is that productive, they can spend 2 years off on another non-ROI project, come back, and spend 2 years on a project with ROI, and the company still comes out ahead.

Most company's aren't smart enough to figure this out, then again determining who these people are is also a problem. That latter part is funny (ironic?), because on the ground floor everyone who encounters a world class engineer is pretty darn sure of it.