Large venues don't use a domestic 240v 13amp supply.
I have worked for the royal shakespear touring company which every week instals a 100kw lighting system and 10 kw sound system into sports halls up and down the country.
They use 3 phase 450 volt supplies which are installed into the venues for this type of use. You could comfortably power a 90k sound system from a single 125amp 3 phase socket with plenty of power to spare.
P.S. It's not clever to rant about subjects in which you are clearly clueless.