I think the term “because they’re lazy assholes” comes immediately to mind.
My local market bought all new heavy plastic carts, easy rolling, and brand new. Ive found and returned the carts from as far as two blocks away.
Most of this is from illegals, barely speaking English, and also another very specific demographic, bussed up to our area.
I was in a store in Spain a few years go, and they actually have carts that easily move sideways. Wish they had those here.
Of course I always get the one where one of the wheels doesn’t work.