The problem is the poor density: power stored is just mass * gravity * height. So if we want to store 1kWh, using a hole 500m deep (about the max for elevator c

The problem is the poor density: power stored is just mass * gravity * height. So if we want to store 1kWh, using a hole 500m deep (about the max for elevator cables, which seems analogous) this would need a 750kg weight. Storing the same amount of energy in a lead-acid battery would only take 21kg, a LiFePO battery only ~10kg. And those don't require digging out a 500m hole, or the supporting equipment to winch a car up and down a skyscraper.