I believe they were usually enacted to protect the nearby properties that the runoff went to, not to help water utilities and water rights buyers make more money, and to protect sources for streams and creeks and rivers.

Also, I don't think most of them were bans. I think they usually just limited the extent of it. Some barrels collecting from the downspouts from your roof--fine. Building a huge reservoir filled by rain--not fine.

And they haven't been all repealed. A few states still have restrictions, such as freely allowing collecting anything that falls on the roofs of your buildings as long as the building weren't specifically to collect rainwater but requiring approval for anything else.