There's an old MIX08 video where some guys from MS actually talk through the design process and everything that went into it with a lot of depth as well as looking at alternative ideas and why they didn't work.
I think I've seen a video where they take the metrics they ask to collect (and everyone I've seen opts out) where the more buttons were clicked in office the bigger and further to the left they moved.
I find it weird based on my comment that windows and office is built around people who choose not to opt out either by ignoring the dialogs or by knowing what it's used for and hoping their metrics make some difference. Unfortunately I think it's mostly just people wanting to be a part of the product who really participate in user voice a lot of the time so we get weird design choices sticking like the mystery meat cut copy paste in windows 11
Sadly, many images are broken, but the blog series "Why The New UI" survives on web archive: https://web.archive.org/web/20080316101025/http://blogs.msdn...