One of the things I noticed in the parking lot, in the shopping cart pickup area, and in the store at large was that I was in the minority of folks that were using the large shopping carts. Most everyone was using the small shopping carts, even folks carrying around kids with them. I've noticed that the carts in the storage area, from week to week, seemed to be getting a growing ratio of smaller carts to larger carts, but didn't think too much of it as I walked past the small cart rows.
But after seeing families shopping with the smaller carts, I think I'm getting it. There's a lot at play here - smaller packaging, more expensive food, and the need to shop around for the best deals. So people are probably doing all their grocery purchasing in one stop for the week less than they did in the past, and they're buying less stuff, and the stuff they're buying is coming in smaller packaging. Shrink, shrink, shrink goes the need for larger carts.