The funny thing is most of these books still aren't making real money (like most internet companies). ESPN and Fanatics are trying to catch up to Fanduel and Draftkings, and most of the legacy/casinos have already lost their hold on the biz except where they are partnered with one of those. Even the Big Two are still giving away too much money on sign-up bonuses and marketing, and a lot of states aren't happy with their tax receipts.
If you are betting on spring training you are either a professional gambler or a problem gambler (or both, if you're not a successful professional gambler). Or you're like me who just bets for fun and sees the losses as being from the same entertainment budget as a game ticket or restaurant dinner (I do not bet on spring training, or hardly any individual baseball games for that matter).
It's kind of funny to think that Disney is in the gambling business now. And sort of reassuring that Michael Rubin had to sell his share of the Sixers for Fanatics to get into it. Kind of doubt that will last, I would bet (ha) that the new Sixers/Flyers arena will have a sportsbook (and there's already one 200 yards from CBP).