I don't have hard numbers on Fortnite, but from what was sussed out of PUBG press releases, it sounded like mobile platforms are way, way more popular by player count than console/PC for them. Fortnite is a little different because it's free on every platform, but I bet they still have similar user numbers just because a lot more people have phones than any console. And I bet this is especially true for the younger generation that Fortnite appeals to.
Of course that's not to say that any mobile user who dips into a free-to-play game has the same long term customer value as a hardcore console player so I'm not sure how that math works out. But it's worth keeping in mind that the player base of any console is dwarfed by phone users and that's a funnel of millions of new gamers who see the PS4 as the only platform that "sucks for Fortnite". I think that could have long term market effects.
Of course that's not to say that any mobile user who dips into a free-to-play game has the same long term customer value as a hardcore console player so I'm not sure how that math works out. But it's worth keeping in mind that the player base of any console is dwarfed by phone users and that's a funnel of millions of new gamers who see the PS4 as the only platform that "sucks for Fortnite". I think that could have long term market effects.