To go through your points, people are still buying new computers today which Windows 11 will not support, so we're looking at a 5 year life cycle for that hardware if those users do not do something like switch to Linux, which we know most people will not.
Using a PC which is no longer receiving security updates is a terrible idea if it's connected to the internet. Continuing to use the device while it is connected to the internet is not a viable option.
Most importantly, even if my computer happens to be 11 years old at that time, if it still works, it still works. I 100% reject the idea that people should retire perfectly fine computers over unnecessary and arbitrary hardware requirements.
What really gets me upset about this whole situation is the marketing around Windows 10, and how it would be the last version of Windows ever.