It actually makes much sense, if you consider how accesible and easy betting on sports has become in these times.
And my personal projection is obvious, it will continue to grow in the coming years, as this new generation of people are going to be accustomed to bet and have access to internet.
We are not longer in eras where one needed to get out one's way in order to bet and gamble. Now one can do it wherever and whenever we are.
The stat of $133b for betting is logical and well aligned, because without live betting options, individual sports fans won't watch live matches anymore. It is always fun to watch a live match mostly when it concerns your favorite league or club sides, after having placed a bet or about to bet, while the match kicks off and people even try to make out time just to be present for the matches, therefore amounting to more views from the public and more money for sportsbooks and tv channels that air these matches with sponsored ads from marketers and content creators alike.