Companies aren't going to ask for college transcripts when offering you a promotion. What matters is your experience and performance, that's it.
I agree that what you say about experience and performance should be the only thing that matters, but it's naive to think that's simply "true", with no caveats, qualifications, or exceptions.
I don't think it's as common as you think as you progress in your career beyond an individual contributor, generally in the tech industry, and specifically at Microsoft I'm 75% sure what you're saying is not the case, with a very small handful of exceptions.
Ditching the degree will also make it harder to move abroad if you want to in the future, since most immigration formalities evaluate education level. This is definitely true when it comes to emigrating _into_ the US, for example.
Also, if you ever decide you need to go back to university (school) to learn about something in the future, I don't know about the US, but in Europe, a condition of entry to masters programmes is always holding a bachelors degree. So if you have to go back to school here, likely you'll be going back to bachelors level. I don't even know how valuable your existing credits would be - I can tell you that they tend to expire in the EU.
So, there are some consequences to this choice. I'm not judging, each to their own, but if it were me, I'd say life isn't a race and unless you are already sat on a potential unicorn and it 'has to be now' Bill-Gates-style, a couple more years while you finish your degree is nothing.