Even if we assume that eSports move completely to PS5 (and that is a massive ask, as you said), how many additional unit sales would that make? 5 million? 10 million? Never the 80-180 million needed for this prediction. This guy not only assumes the eSports-scene moves completely to PS5 (and only talking about Xbox not PC), but also it has to grow massively.
EDIT: But at least we know which analyst recommended Atari to produce 4-5 million cartridges of E.T.
I think his (bad) take is that eSports events will be played on PS5 units instead of PC's next gen for some reason, and that millions of new casuals who have never been gamers before will watch eSports events being played on PS5, and then want to buy a PS5 themselves in order to emulate their favorite eSports players. He mentions how NBA player endorsements can sell millions of shoes, like Nike's Jordan shoe brand. It's a stupid prediction for sure, it assumes not only that Sony will be able to convince eSports events to switch from PC to PS5, but also that the eSports fanbase will grow monstrously over the course of this gen, creating hundreds of millions of brand new gamers.