The move they took is indeed a good one in forcing the hand of the casino owners, and I come and register and fully be regulated. That's if they value the population of gamblers. From there, some business owners just don't want to pay tax and follow laws.
Some among the 2000 will definitely comply with why some will want to leave the market or will want to operate illegally using whatever means they know, which will be a double risk to them.
Brazil is definitely more strict about regulation on the web than many other countries, even if you consider their recent blocking of X, this is one example of how they want to regulate everything that happens on their territory. Maybe it's a tax issue, maybe it's a security issue, I think that's what they'll cover, but I also assume that not everyone will want to allow regulators to interfere in their affairs. After that, we'll see how many of these 2,000+ companies return to work in Brazil, this will be an indicator of who is ready to accept the new conditions.
Only one they know their intention towards regulating it and I think they are taking those decision to protect their own interest. Since if they really want to give their people freedom to choose what they like for sure that they won't do those decision. But guess they want to show how powerful they are and want to regulate everything so that they would take all the favor towards what possible other things they want to implement with this platform in future.
But again let see how this situation end up if they could able to stop their people to access online casino and eliminate certain addiction happening on some of their people. For sure only those casino have big market in Brazil will continue. Then those didn't get much revenue from that country will just leave that country and try other ones.