That would probably be the consumer friendly approach, or at least some kind of life time discount on the subscription platform. At the same time, a perpetual license is typically for the version you buy and that's it (old Adobe or MS Office approach) so I can see the argument for "you got it, and can still use it".

As someone who moved from LastPass to 1Password (after they aged off the lifetime license) though I'm happy and given their growth I'd imagine most of their customers are happy enough with it.