Your sponsor owns way too large a percentage of the building especially given the number of years you have been a Coop. This causes all sorts of refi problems with Banks as well. The Sponsor needs to release units for sale on a steady schedule until their footprint is below 20%. This will serve to bring younger family oriented owners in as you have the size apartments they will be shopping for. These new owners will balance out the demographics and be more interested in upgrading amenities that meet their needs such as playgrounds, bike and carriage rooms, indoor reservable party/lounge/playrooms etc. your building is in a static mode and needs a fresh infusion of capital and owners. If necessary you might need a Lawyer to broker a selling-plan deal with the sponsor.