And surprisingly, it was actually Piggly Wiggly that was the first grocery store to open up their warehouse and allow customers to self-service! [1]

> Piggly Wiggly was the first self-service grocery store.

[1] https://en.wikipedia.org/wiki/Piggly_Wiggly#History

And both PW and Keedoozle were launched by Clarence Saunders (touched on in the history link you give, more under his bio page):

<https://en.wikipedia.org/wiki/Clarence_Saunders>