I spent ~15 years there, left at level 66. Here's the thing people don't want to hear; a lot of people there, particularly management, but others also, are either coasting or not that great.

You have the guy who wrote code in the 90's, became a dev manager, maybe is a PUM now, or still a dev manager, and basically "does emails and attends meetings", goes to the "daily triage" (which has a whole bunch of people in the room), is a member of the "war team" (they probably don't use that term any more). All these people are not "doing" anything useful and there are a lot of them at MS.

This used to work out fine, because the way the August reviews always worked (stacked rank etc.) it's very much a favorites game, "who you know". So you get a pass.

But suddenly there's a reorg and new management comes in (or a flattening; no more dev leads with 2 reports!). And they have their own set of dev leads, dev managers, etc. they want to install. So the existing management gets kicked out, those who still have buddies in other orgs will transfer there (but this gets much rarer now, as most friends from 'old Microsoft' have retired). But the "does emails & attends meetings" guy is out of a job (and is going to cry "age discrimination" because he's 50+, but the reality is he hasn't done a whole lot for a decade, and has zero useful skills now).

PMs; there are WAY too many of these, with their entire parallel org of management. There used to be almost as many PMs as devs back in the day. Other companies don't have anywhere near so many. Most of them can go; back in the day a lot of them would go to the dev's office, ask about a topic someone asked about in email, the dev says "Oh I can just reply to the thread", PM says "Nooo... let me do that" (PM wants to be the one replying to be 'visible' even though they are just a glorified status collector/forwarder).

There ARE a lot of incredible people there, and the best people I worked with at MS are just as good as the best I worked with at the FANGs. But unlike other companies (FANGs, startups) there are a LOT of a really bad/useless people there too. A lot. Although I have no faith that MS is going to lose THOSE people in this buyout.

Engineering discipline is absolutely non-existent at MS. Everything is date driven. The source tree (Source Depot) gets locked as of X date and only "test fixes" can be checked in after that. But the next ship vehicle is months away. So people keep checking in regular code as "test fixes" after the branch lock. One time it got so bad that the build was actually broken for the entire day of the branch lock, and people were force submitting in the evening (everyone expected whoever broke the build to fix it, but... they didn't, so force submit!) to make sure their changes got in before the lock.

Random unrelated funny MS story: The wiki that everyone in Bing used, got wiped out, because it was running on a machine in someone's office that got wiped when they left. We had to have everyone run a script to salvage what they could off everyone in the org's browser cache.