Access vs. ownership is great -- whats the stat on a typical owned car? 90% of the time it is idle and parked.

But access-over-ownership is kinda orthogonal to making things repairable and upgradable. You can still make progress on the latter. I read a comment from an engineer somewhere... he said you can take tons of classes on designing for manufacturability, but he's never seen one on designing for maintenance.

Back to cars, I think the example he used was there's some makes and models known to mechanics as being complete shitjobs when it comes to regular maintenance... you need to take half the engine apart to get to some regularly-serviceable component like a clutch or whatever. I'm sure it was designed to be put together easily in the factory, but when the maintenance is an externality, you just don't optimize for that. Access over ownership doesn't address that.

It does if the original designer & manufacturer is the one renting it out - and is therefore on the hook for the maintenance costs. This is currently the case with Mercedes/Smart and their car2go service - and is probably going to become more prevalent in the car space.