[user104658]

The obvious answer is that there's now limitless other varieties of distraction / entertainment, available on demand 24/7. Mobile Internet, YouTube/Netflix, games have come on exponentially, online gaming (Call of Duty etc., now Fortnite)... Less in-person social interaction in general thanks to technology. A decline in physical contact is inevitable.

I'm in two minds about whether it's a good or bad thing really. Probably a good thing if it's just that kids are having less random sex just because they're bored, but a bad thing if it's because they're not forming as many actual relationships and thus not bothered about physical contact.

I was a good wee boy when I was a teenager, I didn't have sex until I was in a proper relationship . Couple of cheeky blowjobs and quite a lot of... Err... Heavy petting... But no P in V. I was so pure.