I think it's pretty location dependent, but I agree, it's not a very big issue where I am at least. Where I am you still see them, but it's not a massive issue. It'll only be a few, if any.

Apparently, or you shop at stores where the workers are good about retrieving them. I probably see at least half a dozen stray carts every time I go to a store that has carts (fewer for smaller stores, more for larger), and I've definitely had a few roll into my car. I've lived in several different states and it seems identical everywhere. My partner works at a small grocery store and confirms that it's a constant, all-day battle to gather the carts left all over the parking lot and surrounding area.