Not everybody is a fan of online gaming, I have tried some of my co-workers and friends to bet or try to play online game such as Dota2, but they just don't want to switch their gambling experience. They all loved betting with sports. Though, I agree that the eSports industry is generating millions of prize pool and income, thus attracting big time investors and gamblers to engage in eSports. The same reason why there are several TV channels available for eSports already.
There's just people who doesn't like online games.
We just have to consider what they love, if people are already working, I like to assume that they are not playing online games anymore because it requires time to master the games, and some of them are not really a fun, but with male workers, they love sports because they play it also.
Like me, I play basketball and I Idolize a lot of NBA players so I thin sports betting is suitable for me as it gives me a feeling that I can win since I know the game very well, at at the same time I'll be able to enjoy it.