Most 2-3y old kids can walk and when my babies where too small to walk I would just put my groceries in the bottom part of the stroller and in an hiking backpack instead of a cart.

I get that you don't want to make accommodations for people but you might want to think about what leads you all to get so bent out of shape on this one. At the end of the day your argument boils down to "your spouse just needs to work harder so I'm not inconvenienced by the cart she hung off the curb next to the space I wanted." Society is full of people with differing abilities in differing mental spaces and not everyone owns equipment like that and is willing to spend 10 minutes getting it out and setting it up in a busy parking lot while also wrangling their willful, very curious child.