All they have to do is to market their casinos. They're all doing that because they know that the market is expanding and more gamblers are coming in online.
They don't want to deal with the hassle and tiring day of going to the casino just to have the same results. At least with playing online, they can easily find their comfort at their house and relax while sipping their favorite drinks.
They will market their casino after they set it up everything and it is ready to compete with the other casinos. Before they promotes their casino, they will check everything and make sure that their casino can running well and ready to launch. They know that satisfaction from their members is the most important from their business so that will makes them prepare with right and seriously with their work. The casino owner know that competition in the online will be difficult especially if they can not prepare their casino properly. That is why they will make sure that their new type of business can runs without any problem. They even will invite some gamblers to test their site before they launch it to public because they don't want to have a problem with their site. With inviting some people to test their site will gives a chance to know which part is works as well and which is not work so they can fix that before their casino launch to public.
With what I see with the new casinos, they're wrong with how they do it. They think that as long as they have established the website, the casino, the providers are done, they're all good to go. IMHO, that's not how it goes and all they have to do is to make sure that they also have a good security that protects the operation. It's not just all about the wallets that they have, hot, cold storage wallets that they have to protect but also their main operations and users data.