I think the “Microsoft dilemma” is between Making Some Money vs. Take All The Money.
If they publish a bunch of successful games on Steam or on Playstation, they will make Some Money, compared to games published exclusive to Xbox, where they can make All The Money.
By acquiring studios they are making sure that good franchises “don’t make all the money… yet” (on competing platform like Steam, Playstation or Switch, but also Android/iOS)
They could make good games exclusive for Xbox, but given how relatively unsuccessful is the Xbox platform, compared to Switch and Playstation, it would mean that very expensive (to make) games will bleed money