The reason why I am saying that, is what these studios are capable of. Look at Sony 1st party studios. They GOT, HZD, and Returnal. These are new IPs, which those studios made. They have alot of followers, because of those new ips. Now look at the games they made before. You will see day and night.
That is what 32 studios will do for MS. while some studios will focus on certain IPs, other studios will build new IPs. Then you will have someone like Ubisoft, EA, Take2, Capcom, Square, Sega and WB. They have alot of studios, and alot of devs working under them. Since MS is a trillion dollar company, they can basically increase those studios, and fund them to make tons of new IPS, If they buy 1 of them. Simply having 40 studios would mean 1 AAA game every month, and couple of AA in the mix with MS money. That is what having alot of money does for you. Not to mention, 3rd party games will drop on that console too.
On other hand, Sony and Nintendo have limited budgets. If you take out 3rd party games, then you will have few games per year. Banger games, but small output. 3rd party games cover for their small output of 1st party games. Now you have a platform, which can make 1 AAA everymonth. That would be scary thought for them.
This is what happens, when a company spends alot of money. Unless FTC stops MS, they can basically increase their 1st party studios at faster pace. Before 2018, they had small studios around 5-6 1st party studio. Now, they will have 32 studios. All of that, from buying publishers, and studios with their money. Their next purchase could take those numbers in to 40 studios. Add small studios, and you are looking around 45 studios, who are using a trillion dollar company as funding.