The NBA is still happening. We've only had the first week of NFL so it's too early to know about that.
College football is something else entirely, although given the rise of Covid-19 on college campuses, that may be the first to go.
I suppose the determining thing will be if a few big names in any of the professional sports gets sick. Not merely tested positive, but sick, and at least one of them dies. I am not wishing for that to happen. But I honestly think that among the reasons so many people don't take this seriously is that not only do they not know anyone personally who has gotten in, but Herman Cain is the nearest thing to a high profile person who has died from it, and I expect most people didn't know who he was anyway.
Because so much of our culture is founded on Celebrity, until celebrities start getting and and dying, it won't matter much.
Keep in mind that even though nearly 7,000,000 Americans have tested positive for the virus and/or gotten sick, that's only a bit more than 2% of the population. And even rounding up those who have died from it so far to 200,000, that number is approximately .0006% of the population. that's six ten thousandths. So most people probably don't know anyone who has died so far, and the majority of people probably don't know anyone who has gotten sick. Especially since so many who get the virus are asymptomatic or have few, relatively mild symptoms. So essentially, the awareness of the disease simply hasn't had a chance to penetrate very far into the population.