• Discovery CEO David Zaslav said the world will know the winners and losers in the "streaming wars" within the next two years.
• Zaslav said Disney and Netflix are two likely global winners, but there would only be one or two others.
• Zaslav believes Discovery is well positioned as a new streaming entrant because its fresh non-fiction, unscripted content complements existing services.

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It won't take long to separate the streaming haves from the have-nots, according to Discovery CEO David Zaslav.

"Within the next two years, it's going to be put up or shut up for all of us," Zaslav told CNBC's "A View from the Top."

Zaslav said he expects the fiercest competition to come from the streaming services that are primarily focusing on scripted series for U.S. audiences. Apple TV+, AT&T's HBO Max, Comcast's Peacock, ViacomCBS's Paramount+ and AMC Networks' AMC Plus are among the recently launched streaming services competing for eyeballs.

Zaslav said he assumed Netflix and Disney would emerge as global streaming winners, given the leads they've built. Beyond that, only one or two other services that focus on scripted series and movies will be able to gain the global scale necessary to compete, he said. The others will need to band together, either through mergers or partnerships, he said.

"Will there be three? Will there be four? There's not going to be seven," Zaslav said. "There has to be some consolidation."

Discovery unveiled its unscripted-focused streaming service, Discovery+, last week. The service will launch Jan. 4, 2021 with 55,000 episodes from more than 2,500 shows and will include 50 new original series.

Zaslav's goal is to turn Discovery+ into the third major global streaming service after Netflix and Disney, he said. Unlike other U.S.-based media companies, Discovery already has local language content in many European countries. He says the company's emphasis on international programming through the years, such as Eurosport, may cause other large media companies to view Discovery as a essential merger partner or acquisition target.

"They're all probably going to take a look at us and go, holy cow, look at all the local language content they got around the world," Zaslav said. "Then maybe some of them are going to say, 'you know what, maybe we should just roll in with you in Europe or in Latin America. It's going to take us three years to get there. Maybe we should figure out a way to become part of you.'"

While Discovery is entering the streaming wars relatively late in the game, Zaslav thinks increased video viewing during the pandemic will help consumers view Discovery+ as a "fresh" new entrant. But unlike Disney, AT&T's WarnerMedia and Comcast's NBCUniversal, he stopped short of giving investors a specific target number of subscribers to expect by 2024.

"We don't know exactly what the number is," said Zaslav. "We don't want to define what big is. We are going to be reporting out every quarter how many subscribers we have. We have a lot of confidence. We're putting our whole company behind it. But we'll see. We think we're going to surprise people. But we didn't think it was a good idea to say we think we're going to be in five years in 100 million homes. Let's see how we do."

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WATCH: Discovery CEO David Zaslav gives his take on the future of streaming