Re: a plan
They actually already do this, only for 3 years though. ( windows 7 and windows 10)
For windows 7 it started at 70$, and doubled every year (the previous years were not included, so for 3 years the cost was 70+140+280=$490, source)
The increasing price likely has to do with the increasing amount of work and the shrinking customer base each year.
The current lifecycle of windows is a new OS every 3 years, and 5+3 years of support. I think that's very reasonable.
Technology progresses, they need to launch new products, and it makes no financial sense to keep supporting older OSes.
They have also been doing a lot better in terms of backwards compatibility. I don't think i've ever had issues running windows 7 applications on windows 10/11. XP often works as well due to better emulation, most issues i have are related to drivers or old versions of protocols that have been disabled or removed due to security concerns.
Drivers are not really Windows' responsibility to begin with, they are also harder to make work with generic emulation. This is also why windows is going to Apple route of going with generic drivers that work for every device, that way they can ensure backwards compatibility themselves at the cost of reduced functionality in some cases.
Besides, they don't really care about the income of Windows licenses. I wouldn't be surprised if they made a loss on windows as a standalone product.
They care about office 365 subscriptions, advertisements, etc.
They don't employ anyone to make software for legacy OSes, someone just decided to do it themselves. MS doesn't care about XP anymore in the slightest, they don't want anyone to use it anymore. It's giving them headaches because they have to spend 10+ years with optional unsafe legacy protocols in their modern OS because some stubborn people refuse to upgrade. (see SMB1.0, only completely removed from windows quite recently, after a long time of warnings and pleas to please stop using it)