- Politics (in focus) others already pointed out
- When sports do their major events has shifted in the last decades or so
- There's no longer a common TV culture.
That last point started more with Cable TV, but everyone still got 'over the air' so coverage on major TV networks usually provided a foundation of shared culture and events. It also provided major news summaries that most busy adults managed to see a bit of. As if any of us with jobs have time for that these days.
There's also the war for everyone's attention on "Social Media" and the Internet generally.
I don't know why people in these comments are dragging politics into it. That strikes me as a terminally online take and I say that as an self-confessed politics frog.
If anything, the following of current events overall is way down to what it was decades ago by the general populace. People overall are incredibly ill-informed about so many things despite the wealth of information available.
Three things happened to baseball (IMHO):
1. The childhood funnel is drying up and has been for a long time. Kids now increasingly play soccer instead;
2. Take out the nostalgia and you're not left with much. There are too many games, they're too long and not enough happens. Football is bigger than ever; and
3. Structurally I think baseball made some huge mistakes, such as the soft salary cap system that created dynasties like the New York Yankees who could get rich on broadcast rights for a huge media market. The NFL has managed all of this so much better.
I'm not a huge sports fan but I find the systems fascinating. American sports evolved into a 3 pillar system. Basketball season into baseball season into football season through the calendar year. I wonder if baseball's timing over summer has contributed to this decline.
It doesn't explain why it is not discussed on openair channels.