It's more prevalent in South Eastern Europe, where people have traditionally fermented the milk into yoghurt for centuries. The US is actually on par with France, they might make it more of an issue than it is.

https://worldpopulationreview.com/country-rankings/lactose-i...

And yes is seems like the gut microbiome actually has a role in moderating lactose intolerance.

https://biology.indiana.edu/news-events/news/2019/foster-lac...