Keep in mind that this is only for power generation. The issue with solar power is still that it’s unreliable, which means power storage is required.
This can be done with dams (pumps pumping water up) or batteries, but adding to that storage is either expensive or dependend on the environment.
Thus while it’s very effective, its downsides mean that at least currently it still cannot be our main source of electricity. Of course as batteries become cheaper this could change.