I'm not amazed that a family with two littles can comfortably live in 800 sq.ft. but then, having lived in a country where everything is designed with small spaces in mind, I can see why it's difficult to fathom here. Everything's bigger here, including expectations. And, accumulated stuff.
In Nanaimo, we're currently looking to downsize from a very ample 1100 square feet (our BC box is 2200 but we only live in the upper portion, lower is rented), where for 14 years we've very comfortably raised our daughter, hosted family & friends for many parties, dinners and holidays and generally felt extremely content with our lot. Now, we'd love to find something around 700-800 square feet on a 3-5000 square foot lot. They're out there. The 50's bungalows and miner's cottages, where families of many more than 3 were raised, comfortably. Nobody's building them now, though, which I think is too bad. I, too, look at the 2500-3000 square foot homes, with two or even four occupants and wonder....what the heck do people DO with all that space?