I've lived for nearly 16 years in something like what you've described, since it was constructed, a block of 64 flats on a shared ownership arrangment, paying rent on what we don't own. Though similar, it isn't the same, I don't think we could call this a cooperative, there are corporations involved in my case where there don't need to be, so things are much more expensive than they need to be, and not as much gets done on maintenance as needed to actually keep the building from deteriorating, so it isn't really sustainable as stands, but I believe that could be changed around by installing solar hydrogen (Of course!), to replace the building uilities energy power supply, its still difficult to try to get all owners in the collective to agree it needs to be done, and their understanding that it would benefit all of us is still some way off maybe, as well as the funds needed to do it (I expect those to come from solar indexed stimulus, one day soon). As world events are accelerating, the case becomes stronger, as you might guess.

Thanks for posting, it does give some good ideas, I think.