I do think that in time the reason for MS wanting TPM, Secure Boot and newer hardware requirements will make sense. I doubt it's because they are going to make money by forcing people to scrap their old devices.
I would guess that Microsoft think that most people tend to leave themselves very vulnerable to even basic attacks and are trying to improve things. We are fortunate that the high end attackers are not interested in individuals and go for much larger targets. And whatever the big corporations and banks use for security is not always proof against these people and state controlled interference.
If I knew that, I would be rich as a security consultant. Maybe the targets get complacent and think they are invincable.
My old firm had lots of pc's on the workshop floor, all connected to the internet, and people simply abused it. Emails were sent from one pc to the next one and the security was pathetic. They got hacked eventually, but I dont know if any great improvements were added. If I had had any say, all but a few vital pc's would have been disconnected from the internet, and the internal phone system used instead. Any pc's connected to the internet should have been stand alone so that any hacking was restricted. Our IT man would have liked to change to Linux, but the management were too afraid og the change.