You just realized that your post made my point instead of yours hahahahaha

A company that IS the market leader isn't going to be allowed to buy up big chunks of the market. A company that ISN'T, especially one that's new or last placed, like in your example, is going to be allowed to - as they were in your example.

Sony are the market leader by a long way. They would not be allowed to buy EA or Take 2 or Epic (especially not epic because of Unreal Engine). Microsoft wouldn't be allowed to after buying Activision for at least a few years due to the adjustment that the market is going to go through now. Microsoft know this so they won't be trying anything any time soon. If in 5 years time they're still last and sony are still dominant, they will attempt to buy another - and nothing should stop them.