I do wonder if it happens more often now, though.
Yes, I think it does happen a bit more often nowadays. Not really because people are "more evil", but because there is more opportunity.
Back in the day (and still in my corner of the earth), people lived in the same town or village where there parents and grandparents and great-grandparents and their parents etc had lived. Everyone knows everyone, everyone talks. Gossip gets around fast. Faces and cars are known. People watch out for each other. If anyone gives vibes that they are "odd" about children, people will keep an eye on them, will not allow them alone near children etc. You could not really except to get away with it, and people used to feel more societal pressure to "behave", to not embarrass their families etc - not all of them, of course, but on average. So there really was a bit less stuff like that.
As for DS M here, he did not snatch the kid from the bus stop, the distance and the walking had nothing to do with the story. Drugs might be involved. His own personality and life story are the biggest players here. I assume there was grooming involved, stuff escalated ant that's the outcome. He is also one of the people who is unlikely to be held back by societal pressure - by now at least - so the societal changes are not so directly important in this specific case, though interesting on the whole.
By now, the priorities IMO are to 1) find Audrii, 2) charge the culprit, and 3) really think about prevention methods here - not in an angry revenge-centered way, not in a super political way, not with locking kids up "to protect them", but to actually and scientifically analyse if and what we can do as a society to prevent creating such criminals to begin with.