I think it's a regional thing. Veganism spread out from a few "cultural centers" [1] where there was already a critical density of restaurants and shops catering to vegan diets. In places that just got their first local vegan option when fast food adopted Beyond/Impossible, it's still a joke. Other places that are getting their third vegan restaurant have normalized it and veganism has lost any comedic novelty. Chain and family restaurant empires spread out geographically to make use of economies of scale in logistics so there's a natural rate at which this transformation happens.

[1] not culture in general but places that already had lots of vegans

Entirely a function of where you live. Here in the midwest I live in a very liberal city and there are still plenty of places where someone looks at you like you have two heads if it comes up that you don't eat meat. I can't imagine how bad it must be for anyone living in a more rural environment who tries to become vegetarian or vegan.