Greed.

Sure, they want you to run Win11, but chances are you’re already running it, or at least Win10, so there’s not much to gain there.

By making higher requirements for Win11 than neccessary Microsoft makes a killing on Windows licences.

OEMs have to pay Microsoft for keys. And for MS to make money off of keys, OEMs need to make more PCs. And how does MS force/incentivise them to do that? By 80% of the Win10 PCs incompatible with Win11.

Oh, and also, now they get to push their Copilot key as well.

Microsoft has a vested interest in PC sales not stagnating any more than they do, and sometimes it takes an artificial push to make that a reality.