From the side-lines it looks like they're slowly becoming an unstoppable dominant force, what's surprising to me is AWS's / GCP's inaction, they're either asleep at the wheel or they don't see Microsoft's dev mindshare grab as a threat.
But I do wonder if AWS will try to buy gitlab.
I don't know how much control their external board members have, but if an offer came in, the board may be able to force acceptance instead of going public.