Unauthorised third-party modifications and add-ons may end up being part of the solution here. It's already established that this can be a viable business model with e.g. car accessories, games consoles and printer inks. I can see a market for one-off DIY modifications to various things that unlock what was intended to be a subscription feature.

A related issue is the increasing possiblity of devices being effectively bricked because some cloud service or online system has ceased support. Could there be a niche for a company selling improved after-market firmware for other companies' devices?