But even accounting for streaming there's a lot of BYU "fans" who don't watch the games. Think about any ward you've been in. There's a lot of folks who rep BYU on the back of their car or with a t-shirt and are proud alumni...but they still don't watch games or know many of the players.
To be clear, that's not the folks here on this board. But there's a lot of very casual BYU fans who really don't engage at all and aren't really fans of college sports.