Just as the title stated, what do you think will becomes of gambling enirly if we wake up one morning to the news of global banning of football, or a country ban it citizens from participating in football both as a game and also a sport.
Do you think gambling/casinos will lose it popularity since chunk number of their clients are from sport bookies section?
The most important thing you need to understand is that there's always a way that People would choose to take, just to maneuver bans and proxies. We've got VPNs and decentralized browsers everywhere, so I don't think there'll be much of a problem.
But relating it to your description, if it ever happens, people will just find other alternatives to gamble on. They'd definitely lose a good number of gamblers that don't understand the odds of other games in particular.
We've got degenerate gamblers that won't stop gambling for any reason. That'd only create a huge competition between casino games.