Smart things, like smart plugs, bulbs, locks or everything that is remotely controllable and manageable via App or Cloud.

It is not regulated what happens in the case that the vendor isn't able or willing to support those devices anymore. Keeping Apps up to date and new apps if new Mobile OSes arise or keep the light on in general. Right now it all depends on the goodwill of the vendor.

If the provider decides to not support anymore for whatever reason you have a smart brick!