As long as PS sells better than Xbox, they don't really need to acquire companies as it also makes economic sense for third party studios to simple agree on an exclusivity deal with the console leader.

We can already see how most multiplatform games actually perform better on PS5 despite Xbox Series X being a notch better. In fact, some games even lack features on Xbox (Callisto Protocol to date has shitty Ray Tracing on Xbox with poorer performance, Resident Evil 4 Remake having better controls on PS5 compared to Xbox) even without any deals that we know of, while games like Hogwarts Legacy have exclusive content just for PS5, and FF XVI outright being exclusive to PS5. Sony didn't have to acquire these devs to make that happen, the devs get to remain independent and sell their game exclusively on the largest current gen console.

And if and when Xbox sales actually start to match that of PS, they can still make PS+ a better service by having day one releases before going for acquisitions.

It doesn't feel like it, but with ABK, Microsoft finally has parity with Sony when it comes to number of IPs, with Sony still being the market leader with most reach and "true" exclusives that require you to buy the console.