Too many times I have sworn under my breath for someone who left a cart blocking a parking space. I will not be one of those people. Often, as I start to return the cart there is someone who wants it and I gladly pass on the cart.

The final part of his premise I feel is a bit harsh. That said, disabled or challenged in some way are excluded from this theory. The other issue is when a supermarket hires someone specifically to coral shopping carts, as my sister who has worked in the industry her whole life points out, it's their jobs gather them up and move 'em inside. So reutrn them to the corral area but no need to take 'em back inside. Also the more spacious a parking area is also seems to factor in. There are 3 major supermarkets in the town where I live.
One gets most of their carts returned to the cart return area, they have a person to collect and move them inside and the disabled parking spots are right there where the cart return area is.
One has a large lot with many cart return corrals but the spaces per car are a bit tighter and the disabled parking is near either of the 2 entrances. No cart return areas so many carts are left out of the way but not in a return cart area.
The last of the 3 has a small lot, tight parking spaces and is a real pain in the ass to navigate around.
There is also a Grocery Outlet. I don't think there is a specific person to get the cart back up to the area near the entrance(s). The lot is spacious though and people do their part to get the carts to a corral or back to the outdoor area where the carts are kept. Tend to see carts left by the disabled parking spots and I would expect that.