There’s a big difference between promoting a brand new attraction or land versus promoting a floor tile or painted bush with a projector on it.They’ve always done this. It’s just the medium has changed.
There was a 30-60 minute tv special on Discovery or travel channel back when Everest was built about how and why it was built like it was.
And if you go back to the original “Disneyland” TV show there were many segments where Walt talk about how things were done.