Because it's what people grew up doing. Go back 50-80 years, what kind of father-son activities are available?
There's a lot of snarky responses to your comment, but I do think your question has a lot of merit. Watching football/baseball/soccer/basketball isn't like watching an mma match (there's something very primal about how brutal those fights can be), nor is it like watching video games where someone has a shared connection with an activity they do frequently. And the data backs this up. Sports viewership is in decline, and there's a drop in how important sports is to each subsequent generation. And people, imo rightfully, blame things like video games, and social media.
There's a lot of snarky responses to your comment, but I do think your question has a lot of merit. Watching football/baseball/soccer/basketball isn't like watching an mma match (there's something very primal about how brutal those fights can be), nor is it like watching video games where someone has a shared connection with an activity they do frequently. And the data backs this up. Sports viewership is in decline, and there's a drop in how important sports is to each subsequent generation. And people, imo rightfully, blame things like video games, and social media.
So that's my 2c, it's familiarity.