From my limited reading on the subject. It's common for predators to pick on a certain character. An isolated kid who's unlikely to 'tell' and even if they do tell, it's unlikely to be believed. A predator will use blackmail/threats against a family member or likely in this case the likely hood of progression in football.
It's thought that predators know their prey as disgusting as it sounds. It's not always the meek or lonely kid, it's often the troubled kid, a kid from a difficult background, a predator will build up on the outside what looks like a perfectly healthy & supportive relationship, something a kid is often missing. The then take advantage of that.
This is a disgusting character who's obviously used boys dreams of being a footballer to facilitate his sickness.
As many have said, a nonce back then was the weird guy wearing a flasher Mac, suspecting people in positions of trust or power was unlikely, confronting/accusing them was never done.
I suspect like the BBC & Saville, this will be the tip of the iceberg. It's frankly disgusting.