We're just seeing HOW much money is to be made -- mostly by the books and by the "celebrity" analysts/hosts/endorsers these sportsbooks are hiring. It's also the primary reason to watch live sports unless it's a premium matchup or you're simply a fan of a particular franchise or team.
DraftKings and FanDuel have so much money. It's a perfect business plan. They give anyone $500 to $1,500 to sign-up and start betting and, unlike Nevada/Jersey casinos, they don't have any union dealers, cooks, chefs, janitorial staff, housekeeping, pit bosses, etc. Casinos don't make a lot of money off sports betting, compared to penny slots. But if ALL you do is sports betting and have no overhead, you are printing stacks and stacks of cash.
90% of the bettors really don't have any idea what they're doing. DraftKings will match their $500 deposit with another $500, for example, and they'll blow the entire $1,000 within a month.
I got "legal" in 2019 on sports betting and I took my lumps early but I was never down more than $300. Then I realized the only way to profit, for me, is to use the promos/free bets that I receive every day and just cash those in. It's simple math. If you get a +175 bet on one side and -150 on the other, you'll profit, regardless of the outcome.
I'm up about 22k in the last year just doing this. It CAN be done but it requires some serious discipline. About $400 a week -- $60 a day average, a little more on weekends.
The shift was once I quit trying to predict the outcomes of games and, simply, looked to exploit "bad lines", the game got easy. (I play soccer totals for the most part.)