When you used to something there is a chance that it might lose it's value to you, perhaps they are no longer interested in these casino games or they are switching to sports betting because they find it difficult to win casino games...Games like slots can be very frustrating and a lot of gamblers have lost interest in these games because the house edge is always a huge factor that keeps on affecting that players
Most casino games are based on luck. Whereas, when you go to sportsbetting, the chances are higher if you are very familiar with the sports you are betting with. So yes, it is quite frustrating if you are focusing on these luck-based games as it would be very challenging to hit some profits.
As we all know casino games are based mostly in luck, so yeah, if people are switching to a more profitable side of gambling, is very understandable to me. Of course, people want to win good profits and not that everyday you will be on the losing side.