Talk On Corners was massive. Similar size to Shania over here, weren't they? (With the caveat Shania has definitely endured in the public consciousness more.)
There are definitely shows that will sell well to a crowd on Glastonbury weekend.
I know quite a few people who opted to skip out on the G, on the basis of rumours, when Iron Maiden's London Stadium show was announced for the Saturday of. (A show that I remain surprised to discover has seemingly sold out.)