I think the major issue with this concept is that people are going to want a discount. "Why would I rent when I could just buy for that price", even if we won't

I think the major issue with this concept is that people are going to want a discount. "Why would I rent when I could just buy for that price", even if we won't get any more (or heck even less) utility by buying, we think that is a better option, just in case. Given how cheap a lot of this stuff is, it isn't surprising a proper sharing system hasn't shown up yet.