It's few things with chess.
Magnus Carslen might end up being the GOAT, having a once in a generation player will always get attention no matter the sport/competition.
Queens Gambit gave chess a lot of juice. Show had crazy viewership numbers on Netflix, although it's been a while since the show came out.
And most importantly to your question about streaming numbers is that their biggest tournaments/competitions are all streamed on YouTube/twitch, not like you have an option to watch it network TV, so numbers will be high.