It's funny you say that because just now the US is starting to re-consider water fluoridation: https://www.theguardian.com/us-news/2024/oct/04/fluoridation... .
It's also relative uncommon in other developed countries; according to Wikipedia, "Out of a population of about three-quarters of a billion, under 14 million people (approximately 2%) in Europe receive artificially-fluoridated water. Those people are in the UK (5,797,000), Republic of Ireland (4,780,000), Spain (4,250,000), and Serbia (300,000)."
The benefits of fluoridation were amazing. I didn't have a single cavity until I was 25 and had moved away from that area to a non-fluoridated area.
The funny thing is that if you live in Portland, famously one of the few large cities without fluoride in the water, the dentist can immediately tell if you grew up here.
I would guess that in today's world a lot of people get enough fluoride through processed foods being made in places that have fluoridated water.