BOTW has huge mainstream appeal that's the difference between it and prior games it has always been a series that has drawn attention but the gameplay template was distinct so unless the the game was game changing (LOZ, OOT) orpushed hard (TP) it hovered around the 4-5m mark I know it keeps getting referenced but BOTW ironically goes the GTA route (GTA3 was inspired by OOT) where you don't have to be able to do the main story to have fun only BOTW goes further with its absolute freedom. The result is a much bigger following that differs significantly from other Zelda games due to not only more people being able to enjoy the Zelda world and lore but the community opens up in ways that help the game sell for example that video from Peco earlier in the thread that turns the combat into an action game he has an entire Youtube following that tunes in just to watch him play BOTW similar to how large groups of people tune into streams to watch Minecraft and GTA.
This is him just playing the game he's not speedrunning or anything like that he's just playing the game to explore how far its customizable gameplay can go no other Zelda game really did this and it's a sign of how the fanbase has opened up to form and extended community that helps the game sell even further.