"Computers that are Four to Seven Years Old - Although Windows 10 supposedly goes on forever, your computer may not have the necessary hardware to migrate to the current version of Windows 10 during this time period (or in some cases even earlier), and you will be forced to move to another operating system if you wish to continue to be "secure" on the Internet."

This would be news to me. Windows 10 version 2004 requires an x86/x64 CPU that is 1Ghz or higher. If you install the x86 version, you should be able to install on P4 systems that are closing in on 20 years old.

The biggest upcoming change looks to be completely dropping support for x86 (Microsoft dropped support for x86 with OEM installs in 2020). That should still leave CPUs going back to the Core 2 Duo era (and some P4 processors) compatible. That's still 15 year old computers that can run Windows 10 in 2021 with the latest updates.

I have core i5-2500 computers at work that have no problem running Windows. With the slowing of Moore's law these machines are maybe half the speed of the fastest you can get today, but not really noticeable for basic usage and web browsing. The best upgrade you can make is going to SSD, if you haven't done so already.