Although Ken Rockwell has a certain way to put things that somehow make him sound less serious, the same concepts he expresses about APS could be very easily defended with a carefully worded scientific document.
Japanese makers like Canon and others had already pretty brilliantly solved the problem of "intimidating" 135 film loading and unloading. My Canonet and my Yashica T3 brilliantly load their 135 roll in a very fool-proof way and could be loaded with one's eyes closed.
I understand the need for a 126 ("Instamatic") format at the time. Easy loading. Probably the square format was thought not to oblige people to choose between portrait and landscape orientation (that require thinking, and we know how "thinking" doesn't sell well) but, all in all, it made a sense.
The 110 ("Pocket Instamatic") format had the purpose of having a camera enter inside any woman bag without hassle. The idea was brilliant. Woman always (used to) have their bag with them. If we can place a camera in it, we'll sell a lot more film, prints etc. People will have the camera in their bag as a "habit" and many more pictures of family gathering, friends at the put etc. will be taken. Problem was 110 was a bit too scarce in image quality. That lesson should have been learned.
By the time Kodak launched their "disc" format there must have been clouds of grass smoke going around Kodak air conditioning system. The disk format was NOT compact at all, its quality was dismal, laboratories would have had to make an investment, it just could not work.
I remember the Italian magazine Fotografare burying the system with their first review as something like a bad-temper joke.
I certainly don't agree with the "conspiracy" idea that Kodak actually wanted to force laboratories to upgrade. But certainly Kodak managed to behave, with Disc, as if they were the only film and camera producer in the world and anybody was forced to follow them.
APS certainly was flawed IMO by its small format. Whatever the industrial considerations (the foreseen advent of digital lines of cameras and the attempt to produce one line of lenses in the long run) the small format was a huge mistake as it couldn't have involved serious amateurs and detracted them from 135. That is something that anybody should have foreseen at the time and probably they foresaw it very well. So APS ultimately was condemned to be a pocket-camera format only. And that, in turn, would probably deter most laboratories from investing new money at it.
As PE says - an elephant is a mouse designed by a committee - if you want your new format to be too many things for too many needs than it will solve none of them.
Ken Rockwell is right in scoffing at the APS format as a substitute of 135. APS was some kind of a new 126 but without the "need" anymore, he's right IMO.
The concept could have been interesting but the quality target was entirely wrong.
Scanning and slide projection could have been made by APS scanners (they do exists, my Nikon 5000 has an adapter for APS) and APS slide projectors (with HUGE benefits) but that doesn't match with the P&S market segment where APS was confined by its small size.