After discussing it in the Discord, I see that the reward penalty on rentals wouldn't solve this (though it would give a boost to ownership) and that the cooldown also wouldn't entirely resolve the problem.

@eldon1 put forth another interesting idea which is to reduce the energy cap to 25 (from 50), which I think is creative.

All that said, at the moment I'll be honest and say I'm not a fan of any of the ideas. I maintain that I think daily rentals are a utility that we shouldn't kill. My preference right now would be to not change anything.

What I'd love is for the company to look at this in more depth, with the data that is available to them (e.g. on rentals and NPE) in order to suggest a solution (if one is needed at all).