Hah, that's a direction I hadn't considered. That is indeed exactly why vit D is added to milk in the first place. The milk industry claims it's a good source of calcium, but fails to mention it's generally a poorly absorbed source of calcium. Hence the addition of vit D.
Hard cheeses are generally very low in lactose, by the way, but I guess lactose intolerant societies are unlikely to discover this on their own.
Lactose intolerant societies generally have cheese and other forms of curd. Also, babies are generally lactose tolerant regardless, losing this tolerance later.
Hard cheeses are generally very low in lactose, by the way, but I guess lactose intolerant societies are unlikely to discover this on their own.