It's worth remembering that this conversation was in response to claims that Elton should have played the legend slot because his crowd dissipated during the show...
which is still funny 🙂🙂
As I think someone else mentioned, he did headline (and curate) a sold out APE last year. Previous recent headliners of that include Stormzy, The Strokes and Jungle, all of whom could headline the other stage so I don't think it's totally unreasonable. That said, he might be better off going the Little Simz route and doing an afternoon slot on the pyramid which would probably get him more exposure.