I don’t think @LexiconDexicon said hydropower is no longer needed. They just said there’s no need for so many dams anymore, and I think that’s correct in this case.
A lot of these older and extremely underpowered dams were built in important riverways. They decimated salmon runs but produced only small amounts of power in return. For a recent example, Elwha Dam removal in Washington State comes to mind. It and another dam produced only 38% of the electricity needed to operate one sawmill, but it killed salmon habitats. You can read a little about it here: en.wikipedia.org/wiki/Elwha_Dam