The audience for sports bars is obvious - people, who are interested in certain sports competitions. Often quite gambling people, who are big fans of drinking while watching, eg, football match with your colleagues. Sports bars make good money - especially, when there are some high-profile matches. You can increase your earnings, by introducing special software, which broadcasts various matches, games on TV screens. Such software is usually called TV rate.
So what is earnings based on??
At that, that a sports bar can accept bets on sports. Of course, a bookmaker license is required, specific business plan. But it all pays off pretty quickly. Without software, it is almost impossible to display all the necessary competitions. And people should see them, who made the bet, to be sure of the integrity of the service, provided by the sports bar. Thus, In sports bars you can even accept bets on virtual sports, which are more than popular today. Regarding software implementation, there are companies, who turnkey it. And the business only needs all the necessary equipment.