I understand your idea and while it looks sane in a specific aspect, like security and having more pressure to not stuck and build IT on legacy please consider the following:
Few Personal, Business, might not upgrade to anything because of:
- financial reasons (debts, spending limits)
- Their app being incompatible technically
- Their app being compatible but 3rd party vendors that use it, do not support the new apps (seen this many times esp with Office)
- It's legally tricky with licensing as customers may use perpetual licenses, that give them the permissions of using the software within these boundaries. So I cannot see how this will work with perpetual licensing at all.
- Legal requirements exist to use recent and updated software for security reasons, like EU GPDR and security frameworks / industry standards