Do they need to do the updates to get the telemetry?

I imagine the updates will stop for older models about the time they decide that supporting that version of whatever hardware costs more than they get out of doing it.

Not so sure, they're still adding a lot of features to non-AP cars despite the fact that they're not the latest & greatest any more.

They are still in their brand building phase so they get a lot out of generously supporting older vehicles.

Lets see if they are shipping high volumes in 2020 and still supporting 2012 cars.