I think it is reasonable and understandable if they have to stop this exclusive bitcointalk wager contest because it is clear that the total wagered amount for every round is not that much.
As I remember it correctly, the latest one is the 3rd contest and they have spent $5000+$1500+$1500= $8000 while I think the total wagered amount on all those 3 contests is not even close to $1M.
Means that it is not really profitable for the casino to spend more money on this kind of contest and perhaps they can simply add more onsite contest where all players can participate.