Not even close. Pretty sure both LoL and AoV are around 2-3x larger than Fortnite.
This is the (analyst) data everyone is citing: https://www.superdataresearch.com/us-digital-games-market/
This is the (analyst) data everyone is citing: https://www.superdataresearch.com/us-digital-games-market/
I would argue that Twitch has had a really strong role in making battle royale games popular -- they're extremely fun to watch in comparison to MOBAs which I'm starting to realize are fairly dull in the beginning but the anticipation of what happens mid-game to late game makes it exciting.