The chances are low and odds are against unless the new casino aims to be a specific game focused gambling platform. The long term success will happen but there are questions have to be answered by the team before going to accept this decision: Will they be able to advertise among the new casino and gain the trust of players among all the old established brand casinos?
It is very easy to attract attention with good advertising, welcome bonuses and a beautiful and convenient website design. However, it is much more difficult to make sure that those who came to play remain there forever. It is most difficult to acquire regular visitors.
It is not that easy, good advertising such as signature campaign or forum banners does not give any guarantees that people will come to the site. Beginning phase of a business including gambling business is the hard part as it needs so many hard work as well as patience from the owner. I can even say that keeping players to stay is easier than attracting new players to come.
As far as I understand advertising on the forum for most of these casinos is not the only one. They are also advertised in other places in order to reach the target audience as much as possible.