Yes, flow batteries, gravity batteries and high water storage will all make their presence felt. Those ~~20-50 tonne bricks they haul and drop would be costly,

Yes, flow batteries, gravity batteries and high water storage will all make their presence felt. Those ~~20-50 tonne bricks they haul and drop would be costly, but I expect them to make them as strong walled brick shapes, with a lower cost fill - be wise to add salt to limit freezing in cold weather.