What makes you think they are? I, for example, find it weird that both “From My Family To Yours” and “Chris's Bargains” have over 100,000 items on sale. That, at least, seems like misrepresentation of a business as an individual seller.

”And different ones, too”

How do you know they are? 2 of the 3 ship from Florida; the third doesn’t mention where it ships from. Could be chance, could be a sign that some of them are the same seller.

(And no, I have no idea how common it is for a merchant to have multiple stores on Amazon. It is fairly common on other stores on the internet, though, as it doesn’t cost much to create another web store, and it allows you to target different market segments)