This idea could be cranked up a notch if polarizing was eliminated—with 16 “wide” slots, adding two centered ground-pin holes—one for each group of four slots. You could only plug in two grounded appliances, but heck, that’s all anyone would ever need 99% of the time, right?
My house was built in '69 with all #12 (not AL) and EVERY Receptacle WAS like this. The UL Marking is to the Left of the Cover Plate Screw hole (above in the picture) and the marking to the Right is GE.
This is a great example of things that had a limited availability, being made obsolete by progress. The plugs that this is sized to take were the "standard" before 1960. A very common receptacle was a "triplex:" three receptacles in a single-gang box. Triple-switch devices were also made. In the '50's, receptacles assumed today's shape & size. Not too long afterwards, the ground pin was introduced.
There were also receptacles that had terminals for antenna wires. Only a few years before the advent of the GFI, there was a big fad of using low-voltage devices in kitchens & baths; you could hear the relays clicking in the walls.