Cool games are for cool kids only. Casinos are more for an adults. Casinos will never have console or PC games among betting ones. The answer is simple - there is never a big audience for that. You wont find a lot of gambler that will want to place bets on such games.
Do remember, adults will die and the cool kids will be the ones left.
We are already witnessing changes in the sports and casino gambling industry. You do know we have e-sports (electronic sports) now and electronic leagues are also populated by many fans. DOTA, CSGO, and more.
I won't say that traditional sports and casino games will be forgotten but it's not bad to add more flavors when new gamblers are looking for them.
Way, way, back, PC games gambling is only done by physical betting using hard cash PVP, most of the time only players are the ones making the bet before they start the game. Now, even fans can do it by visiting gambling sites that made it available.