It is ridiculously uneconomical to create the volume for pumped storage. For context, with 100 meters of pressure head, you'd need 25,000 olympic swimming pools worth of water to store 12 hours of electricity from a 1 GW electric plant with 70% roundtrip efficiency. At a cost of $216/cubic yard of excavation, that's over $17 Billion. If you can make 3 cents per kwh profit buying at low times and selling at high, it would take 129 years to cover just the costs of digging the hole at the high spot. Then you need to dig another hole of the same size at the low spot so you can reuse the water.

There are really only 3 options - dam up a watershed so you can get a huge volume without much structure, build your resevoir on top of a mountain so you can get much larger pressure head and thus require less volume, or reuse a hole you were digging anyways such as an open pit mine. In all three cases you are heavily constrained by geography.