The PM role is not at all about finance or marketing. PMs at Microsoft are expected to be technically competent and depending where they're stationed, may regularly contribute code. Julie Larson-Green is noted for her expertise in UI/UX. If anything, this exemplifies a shift to focusing on the end-user.
> "PMs at Microsoft are expected to be technically competent"
That has most certainly not been my experience with Microsoft PMs when I lived in Seattle. There were more than a few who had zero experience writing code in-industry, and many who I wouldn't trust with a product at all.
My experiences with PMs were universally good; these are people who would look at ideas in-the-baking and find ways to improve them, run interference for a number of projects, put together decision-guiding research, and generally somehow manage to bring things together.
There are bad apples in every bunch. The reason MSFT has so many PMs is not that they are under-competent; I suspect it has a lot more to do with the fact that it is a large organization that is often unable to silo teams from each other effectively.
As a former PM, I can confirm that many of them are not technically competent. I would say a good number of my colleagues did not have the engineering rigor to get a good mark in any CS class with a heavy engineering/programming component.
So your experience in OSD translates across a company of 90k+ people? Seems legit. I have met some PMs that probably couldn't write a line of shipping code too, I have also met some highly competent ones. I guess, like all things involving large numbers, there is a distribution, not all fall in the tail.
There's technically competent and then there's 'can sustain working as a developer for an indefinite length of time.' Some people are just not a good fit for being a developer. The worst though are people that have given it up but still try to maintain the cred.