If sports bookies are banned then a lot of people will stop gambling. Majority of gamblers are into sports betting and banning sports betting means that majority of the gamblers will be affected. Sports betting is the only betting that involves real humans and so it has attracted more sports enthusiast. When you have interest in a particular sport, the next thought is how to make money from the sport by betting on the sport since you have reserved knowledge of the sport. The only reason why I picked interest in football betting is because I watch football. 

In my mind's eye, I have visualized the number of persons who are seen in a betting shop daily placing games on different sports. In some neighborhood, casinos are not popular compared to sports betting and so imagine what will become of sports bookies of it is banned. Such bookies will lose income drastically.