The MLB, NBA, and NHL Hemorrhaging fans?

I've heard that the MLB, NBA, and NHL are hemorrhaging fans?

The NFL is gaining fans due to Taylor Swift/Travis Kelce romance. But why are the other three losing fans (and in the case of the MLB and NBA, at a precipitous rate)? I've heard people blame Lebron James for declining NBA fans, but I think it's more than that? I'm not that familiar with MLB and NHL attendances, so I want to know what really is going on.