Let's say it was true. What does it even mean for users? macOS was on version 10 for something like 20 years. There were big changes in that time and compatibility for older hardware was dropped along the way.
Version numbers like this are arbitrary. They could have released Windows 11 as Windows 10 21H2 and it would have changed nothing about the scenario where some people can't update and their version would stop receiving security updates.
Even if it was true, 10 years is a long time. You can't trust anything any company says will still be true after 10 years - even if you have the same COE, their priorities and supporting executive team are likely to be different in 10 years.
I already said I didn't believe it for those reasons and others. It was a cynical lie to boost short term adoption that was clearly going to bite them in the ass later. Imagine if they now say Win11 will be the last version of Windows, no one would believe them and it would have no effect. The lack of trust creates problems in adoption of windows features, UI frameworks, App Stores etc. and this has very very negative consequences for the Windows ecosystem which is in a very sick state - I think maybe terminal. Also internally the internal departments lie to each other as well. Not even other departments will take dependencies and if you have no users for your features you lose the ability to justify funding - the perception becomes reality and a huge amount of effort and opportunity is wasted.
Version numbers like this are arbitrary. They could have released Windows 11 as Windows 10 21H2 and it would have changed nothing about the scenario where some people can't update and their version would stop receiving security updates.