I live in walking distance to my supermarket and often gather shopping carts and wheel them to designated parking spots. I think the answer is laziness/entitlement just like the selfish SOBs who DON’T PICK UP THEIR DOG POOP after it poops in public areas.
It’s nothing more than that. They can’t/won’t perform a common courtesy because it’s so easy not to.
I always take at least one cart from the parking lot on my way in to the store and return it to the cart corral when I leave. If everyone did this, there would be no need for a cart chaser til the end of the day.