It may well be that that sketch (and there may have been others - it was a very famous and parodiable advert) had something to do with it. But then it's a question of whether they created the Hovis Delusion* or were just among the first to succumb to it...

* Of course, I would like this to be the title of my popular science bestseller, but I see that someone has beaten me to it with the Mandela Effect.