The PC and Windows became a thing because Gates cut deals with hardware OEMs to use DOS, and outsource the OS work to a company that does only microcode software, hence the name. That meant hardware devs could disentangle from high level shit and focus on the hardware, which saves them money and effort, and in exchange Microsoft gets paid via OEM license and completely locks down the PC market.

Yup. It’s the Wintel juggernaut. While the license fees are much lower for pc manufacturers they are still a huge source of Windows revenue. Enterprise and cloud licenses are making it less important than it used to be, but they intend to continue to capture as much rent for windows as possible.

Win11 is more secure than prior releases, but certainly not better enough to justify buying new hardware.

It was called the "line in the sand" when they did this with Vista. I think they have some sort of belief that if people are not needing better and better hardware the whole PC market will falter and they will not be able to sell as much software. This might even be true but as with vista this approach normally just pisses people and companies off.