Does your house include maintenance and security upgrades forever?
No, but the lumber and drywall and screws and anything else I might need will still work. Unlike when operating systems are abandoned, and then new software simply doesn’t function. Imagine trying to hire a handyman to work on your house, but all of them say “nope, that’s an old house version with pipe sizes and stud spacings and drywall thicknesses we no longer work on. We would be happy to sell you an upgrade, otherwise you’re on your own.”
Suppose, also, that you had a security system but they just decided, even though it still works, nope, we no longer accept alarm signals from your outdated system, you need to buy an entirely new system.
So it is with Microsoft software.