It's not because they consolidated and now have a dominant position in the market. In fact the opposite.
Dominant or retarded position... the outcome was always going to be the same.
You dont spend almost $80B aquring publishers, cannibalize actual sales of your games and give them away in a sub service, all for a user base that cannot generate enough revenue to sustain all that.
That just makes no sense.
And even if that is your strategy, then you have to get your sub base for your service up to some ridiculous numbers. Now how consolidation is justified is that you believe you need to do that to provide enough content to draw in more subscribers. However, if that fails, you need to not only put that content on the platform that generates sales, but also increase the subscription cost.
But even if you did succeed, and you then become the dominant market platform, it would be at the direct expense of everyone else, which basically makes you a monopoly, and then guess what, prices will still go up cause now you answer to no one.
MS got itself in this position because they were stupid and did not actually understand the market they were in, or even their position in it. They never have, and everyone at MS who understood it (OG Xbox and 360 era) no longer works for them.