Quoting the article below, “The U.S. is the leader in dam removal, proving that the risk and cost associated with old dams can be eliminated altogether in many cases. In the past 30 years, the country has decommissioned more than 1,200 dams.”
Dams wear out. Many would now be too expensive to replace. Furthermore , the basins created by the dams have often silted up to the point that water storage is reduced to a relatively small amount.
None of the foregoing considers ecological effects of dams.
People still need water but we can now recognize that dam water is not “free” in terms of money or its effect on nature. Nature, people and money must all be considered together as we decide which dams to rebuild and which to remove.