It tends to be geographic, so if you live in a region that’s able to deal with lactose, you’d have the impression lactose intolerance isn’t super common. But entire regions are lactose intolerant, like Southeast Asia (including China) and about half of India.
Basically anytime you see dairy as rare or non-existent in a region’s traditional cuisine, that’s why.
The fragmenting of teams needs more attention. My group uses a follow the sun model that has our team split up across at least seven countries, plus a decent chunk are always contracted through a vendor. Add in remote workers, and it’s very difficult to see an effective way to organize.