There was an article in Scientific American re a study published in Science about why people don’t return shopping carts. See: https://blogs.scientificamerican.com/anthropology-in-practice/why-dont-people-return-their-shopping-carts/
There are people in the parking lot who always return their cart, individuals that never return their cart, those that return when it’s convenient, patrons that feel pressured to return the carts if a cart attendant or adjacent car owner is present, and customers with kids who return the carts as if it’s a game when the children ride in the carts.
Certainly this is like vegans. There are those that will never buy vegan food, people who always buy vegan food, those that buy when it’s convenient, customers who feel peer pressure to eat vegan meals sometimes when being watched, and vegans who see it as a fun game to explore new foods and restaurants and take others there. Which are you?
For more about behavior and vegetarianism, see:
https://www.vrg.org/journal/vj2006issue1/2006_issue1_beliefs.php