Unfortunately I don't think the gaming market specific numbers are publicly available. But Microsoft is overall a much bigger company than any other in the videogame industry. Surely that matters too as it means they can potentially outspend all of their competitors (eg use another profitable division to fund the videogame division to gain market share and competitive advantage)
Some of these numbers are public, others are internally tracked by the industry even if not shared publicly (only between the companies involved), others can be guessed and when regulators ask for them to the companies they provide them to the regulators.
Yes, MS can outspend many companies and they are doing it spending almost $100B in a few years on a market where they had billions in loses. But even doing that other companies perform better than then in gaming in terms of revenue and profit, and in the case case of consoles Sony outperforms them in basically any metric.
I also have to wonder how many Sony fans would even be complaining if Sony got a wild hair up their butt and went out and bought capcom square or namco etc? I feel like it would be complete double standard arguments everywhere.
ABK represents a small portion of the console market to the point that making their games console exclusive wouldn't significatively the console market (and even less PC or mobile markets), and for this reason several regulators approved it and I expect the remaining ones to approve it once all the paperwork is done.
Capcom, Square or Namco (separatedly, each one) are several times smaller than ABK, so getting them exclusive would affect even less the market than doing it with ABK. So I think regulators would approve their acquisitions too. But in any case, as with Mojang, Zenimax, ABK and Bungie, it would be smarter to keep them multiplatform if acquired because since to make them exclusive wouldn't change the market enough and only would highly decrease their revenue and profits, it makes more sense to keep them multi.