Sure, but that really isn't that important in the dynamic here, based on a probably complicated web of business conflicts that I probably don't even understand that well.
Packing even 500 people into a nightclub may not be even be allowed for months, and months in places like California, or New York. Clubs, that aren't backed by major capital, (think Hakkassan) aren't going to be able to re open. The money is gone. Small clubs operate on thin margins, that need capital to pay for mid tier high tier acts to bring in people and sell tables. One event pays for the next, and the bottom has fallen out.
Even if it is, do you want to open your club and have your patrons sign waivers about lawsuits for Covid 19 lawsuits? Or deal with the fallout when 78 people are infected, and posting on social media they got it at your club? Hundreds of people dancing, spitting, breathing on each other, passing around bottles in confined spaces, and probably 15% going home or after parties together is a recipe for outbreaks.
it's a massive problem, on about a half dozen different levels. And that's just clubs, much less huge events. Who is going to insure a 5000 people event? How much extra overheard will safety precautions cost? it's a nightmare.