Microsoft Gaming revenue 2020: 11bn USD.
Valve (estimated) 2017: 4.3bn USD.
That is as close as we can get.
That Valve estimate is from SteamSpy and only includes game sales, not microtransactions, DLC, the marketplace etc. which is probably a very large portion of their revenue. Hard to say how much ofc. Where exactly is the Microsoft number from?
Anyways from what I could gather they had around 9bn revenue in 2017 if we were going to compare the same year.
- Switch - 27m
- PS5 - 15.5m
- Xbox Series - 10m