Honest question: are ads for OneDrive on Windows any worse than ads for Chrome on Gmail? As a user, I see them as equally annoying (based purely on the consequential effects and not the implications).
Also, having any OS collect your data is an incredible privacy violation, since, Operating systems, by their very nature have incredibly overarching access to essentially everything you do. And then, on top of it all, they serve ads.
Essentially, so far, software was either "sold", ad supported, or data supported, or both ad and data supported. Windows is trying to triple tap.
And again, the OS has access to absolutely everything. Having a platform have access to a slice of your life feels very different from having a platform have access to everything.