There's only one thing in the world of gambling that could compare to Macau in its glory days

In its glory days Macau's casinos were bringing 40% margins and showering the gaming industry with riches.

But thanks to China's anti-corruption drive, that's all over for now. Since last summer Macau's 40% margins have turned into 40%-50% casino revenue declines as the Chinese government cracked down on gamblers headed to the island.

Luckily there's one business in the world of gaming that could deliver comparable returns - fantasy sports.

"The business has the potential to be as big as Macau over time, said Jason Ader, one of Wall Street's most brilliant gaming minds and the founder of SpringOwl Asset Management.

Ader, who cut his teeth as an analyst at Bear Stearns, was a guest on CNBC's Fast Money on Wednesday. He said that soon enough fantasy sports will replace slot machines as the primary way Americans gamble.

"Millennials... don't like the traditional gaming experience," he said. They prefer gaming experiences provided by companies like FanDuel and DraftKings.

All you have to do is look at what Vegas has become - and where China wants Macau to head - to see that gaming isn't what it used to be. Now young people are spending more money on liquor, clubs, shows and food than on casino games.

Get with the times.