It's really hard I think. I mean if we assume sports betting is never going away (Outside of the US at least, sports betting is barely controversial and is basically now, unfortunately the oxygen of a lot of the whole sports industry).

A lot of the large sports betting orgs (Unibet, Bet365, Ladbrokes, etc) allow betting on at least some contests that aren't sports. Like elections, Eurovision song contests and so on. So it becomes difficult to draw a line between the things that are legal to bet on, and those that aren't.

And as we know, even if two things are clearly on either side of what should be legal but you can't make a good distinction of what makes one of them illegal, it tends to be the case that both remain legal.

I think the easier short term fix for this is to have KYC laws and actually enforce them.