Next year Windows 10 goes End of Life. Microsoft will undoubtedly push windows 11 hard, but a lot of machines won’t support it leading to a few economic points of interest:
The demand for new machines will be high, driving up cost.
The supply of unsupported machines will be high, driving down the used market.
Are you all ready?
11 has artificial hardware requirements built in that will prevent it from installing on a lot of computers (possibly most computers deployed in the world, at this point) which is the main issue. All those non-technical home users who bought a brand name prebuilt PC in 5, 6, however many years ago that still works just fine will not be able to upgrade.
They will be left in the lurch unless M$ relents and removes those requirements (unlikely), they all learn to patch them out themselves (extremely unlikely), or they all go buy new computers with newer hardware (extremely annoying).
As me and others have said all over this thing, Windows 10 no longer getting updates doesn’t mean it’s mandatory to update. Most of the users you describe will not notice or care that security updates die out and they will just take whatever runs in the next PC they buy, as they normally do.
This mostly matters to power users and corporations. If that. I’m arguably a power user and have zero intention to upgrade my legacy Win10 machines for this reason, either.