While I do agree with you that livestreaming is overstated, just about everything you said in support of that seems irrelevant. People actually do watch home run derbys and golf. Although there are multiple people involved, these are in fact single player games, and you compete only in the sense of playing the same game at around the same time to compare scores. To a lesser extent, things like bowling and curling and pool also get airplay. And every Olympics, there are solo sports like gymnastics and diving and archery and (of all things) "solo synchronized swimming", as well as minimal-interaction competitions like a million variations on races (footraces, skating races, swimming races, skiing races, skiing and then sometimes shooting things races, luge...).
These things aren't as popular as football in the US, you say? Well no shit, neither is any given livestreaming game. Not the point. These things are all popular enough that they got devoted time on TV even back when TV broadcast much more limited content at any given time.