Me and DH in our 60's and we don't regret our decision to be childfree. Never regretted it for a minute.
We decided 40 years ago not to have them and one of the reasons was the crap world we live in. Now the world is even more crap and we are so pleased we made that decision. I would be worried sick about their future with climate change, food shortages, water shortages, rising sea level etc.
None of our child free friends have any regrets to my knowledge but plenty of our friends with children say if they could go back in time they would not have any.
Lots of our friends have grown up children, some have grand children, a few have great grand children and yet a lot of them are still worrying about their children and getting grief and hassle from them. Others are worrying about their grand children. Seems it never ends.
I would say surely it's better to regret not having children than having them? Also surely it's not easy to regret something you have never had? If a child free person had had children they could have had health problems. they could have caused health problems to the mother, they could have turned out to be a rapist, a murderer or just a nasty person. They could have decided to cut contact with their parents.
As I said, me and DH are very happy and have a happy marriage and are very much still in love after 40 years. That may well not have been the case had we had children as so many relationships breakdown because of children