I read all the pages and watched the video. What I walked away with was that a) the original Toyota seal design was too stiff, which is why they redesigned it; b) the new seal design, while improved because of compliance, put the sealing lip in the wrong place, which is why it makes sense to flip the retainer. I didn't see anything in the video, or in the writeup, to say that the original seal design would not work with the original retainer installation - maybe I missed it. Given that most original seals don't leak until well over 100,000 miles, I'd say that the original combination, even if not ideal, did OK.
Now, it is possible that some aftermarket seals are crap and won't seal. I said it before and will say it again - my 1960 replacement seal did not seal well, so I took it out and replaced with new Toyota design. But other seals do seal just fine, and do place the sealing lip in the sweet spot of the retainer. This one does that (on the right):
I got my fingers dirty enough: