Apart from the politics of the situation, you will see a contraction in the number of sportsboks, pokers and casinos anyway.
The industry climate is one of mergers and aquisitions, as happens in all industries that are coming off age.
You will see a few very large groups be the backbone of the industry. Smaller places will fill niche markets.
Granted, the legal situation has a huge influence on some of the places not permitting US punters. But even without that, a lot of places would and will focus more on niche markets and leave the overall market to the giants.
When you look at Brick and Mortar business, that’s how it always works.
Don’t worry, there will always be plenty of opportunities for Americans.