Does that mean that there is some smoke and mirrors when, eg Taylor Swift, says they sold out the concert in minutes? Or are the mega acts truly that high demand?
You can get the seats into "baskets" (reserved) in minutes. In my experience they will not sell out for some time as they usually keep dropping back into inventory. "Sold Out" is a matter of opinion. There are usually lots of single seats left sometimes for weeks or months. The promoter decides when to label the event as "sold out".