If that's the case then we might employ Mickey Mouse and use him as our poster boy. Surely he's more marketable then Rooney.
That's the problem with this club. They think that the vast majority of their fans are stupid
Rooney is still a big deal in terms of what he has achieved and because of that he is recognised world wide. Better players doesn't mean better marketability.
If you compare Eddie Redmayne and Arnold Schwarzenegger, Redmayne is a way better actor, younger, fitter and even has an academy award. Whereas Arnold is past it, fat, couldn't act even before and is old. Yet a product would probably sell more if it has Arnold's face than it will if it has Redmayne's. It's not fair maybe but that's how it is.
Whatever you claim to know about marketability isn't true. Rooney still is very marketable and that can't be recreated by de gea or Smalling yet.