I just have to assume that Norwalk has some big overhead expenses (like insurance) that would not make it profitable "with 83% revenue lost".
Since lots of other expense are zero when it was closed (without revenue). A low overhead business will make money being open half the time since closer to half the expenses were not incurred while closed.

Anyway, I was able to race on May 30 at Farmington Dragway, NC. Great turnout of racers.