They didn’t get shut down, they shut themselves down because processing was so expensive.
No one has a crystal ball so it’s impossible to predict the future.
If you’re just starting out, I would suggest a mix of US and Non US casinos. If you’re really worried about losing the US, you can always ask for a CPA commission rather than Rev Share. And since you’re new, that may be a very good thing. Yes you may lose out in the long run, but you’ll make more now which you can use to build up your site.