Yeah, I'm not sure that fewer people will own computers, I do think people will shift to much longer upgrade cycles.

Or live with lower specs. You can still get a Chromebook for $200 and install Xubuntu on it. I did that, and it's perfect for video conferencing and web surfing. You certainly can't play CoD on it, but even if you're looking to play games there are some older games that run on it just fine.

it just depends on how you define computer.

people will own an increasing number of dumb terminals connected to rented services.

does that reduce the number of computers? well, no..

so, imo : the trick isn't to reduce physical ownership of devices, the trick is to make it so that you need Big Iron in order to do anything.

One way that might be achieved is by forming social and cultural dependence on models so large that no one individual could possibly run them...

The second hand market is going to have much much more lag. But it's very unclear that this is going to sustain indefinitely.