With Microsoft its probably mostly (3), with maybe some degree of (2), with (1) maybe, especially in the political salience, being a plus in the eyes of some decision-makers but not really driving the decision.
There are firms (and public agencies) where the relationship between those factors is very different in driving RTO mandates.
Why not extend the baseless paranoia and say it is because they want to see auto company profits go up? And also support petroleum companies?
Or is it just real estate that is boogeyman secretly running the country behind the scenes?
No spherical CEO in a vacuum, maybe.
Now, I would imagine that there are quite a few in the top management who originally signed off on that expense. Probably the same people who were talking about replacing offices with cubicles since 2015, which means Satya and his inner circle. So now they've spent a lot of money, they have to do something to show to the board that it wasn't wasted. Which means filling those buildings with employees, whether they like it or not.
It's not an explicit decision making factor, just something that's in the background that has contributed to the overall idea that "RTO = good"
These decisions are all being made by vibes, after all, not by a cold rational analysis
Just follow the money, it usually works very well. Sometimes, people are just dumb on their own and/or as a group but I don't think thats the case here. Tens of billions if not more in lucrative real estate is at stake.
These executives don't like looking dumb and these billions in useless investment are statues to them looking stupid otherwise.