I don't think so. Home Depot is clearly a big hardware store / lumber yard. Costco may carry many kinds of merchandise, shelved roughly according to type, I don't think it really qualifies as it has unspecialized staff (and very few of them), little selection within each type of item, and probably its only true "department" is the tire department.
The only thing you list that could arguably be a department store is Walmart, and I think the reason it's not recognized as one isn't because of its size, but because it's been drained of all glamor.
And none of them (at least in their non "super" sizes) are subjectively much bigger than the old mall department stores.