The concert you want to go to isn't SOLD OUT because consumers bought all the tickets. It is sold out because some online ticket resale company bought all the tickets and is now re-selling them at 5 times the price.
THE CURIOUS CASE OF US TICKET RESALE LAWS - "Did you know that reselling tickets in Hawaii is completely legal, except for boxing matches? Or that in San Francisco you can go to jail for selling a ticket on the street but it’s legal to do so from your home? These are some of the of the peculiar laws I’ve encountered in my research of ticket resale laws across the United States in the past couple weeks."