Interesting (would be more so with more data, such as the writer knowing their level of lactose intolerance, as it's not a black/white thing), but yeah, very un-scientific. From the cost point of view, I prefer to stick to lactase tablets (I get from H&B in the UK), on a per-need basis. If I used one every day (every other meal), these would cost £12 for 3 months without discounts (there always are), so some £40/year. I use maybe one a week! So the cost is significantly less and I don't have to keep up a regime of treatment (with bloating) every X number of months.
So, thanks, but no thanks 🙂 Milk and yoghurt wise, I've switched to plant based anyway. Try 'em out!