Would prohibition really work? It's not like there isn't already a large network of illegal betting in place for all the bets that can't happen legally... it would simply make them thrive even more.

Making things illegal/banned might feel good at first, but if it's barely enforceable and/or the demand for that thing remains very high all you are doing, as a state, is foregoing on a lot of taxes while not even diminishing harm often (sometimes even causing your own harm... I'm looking at you "war on drugs"... and before that the alcohol prohibition).