I should clarify what I mean that he's absolutely wrong.
There probably were pre-smog era engines where manifold advance was used. But he is wrong that it was universally used, and he's wrong it changed with the introduction of emissions requirements. And it's certainly not a 'band-aid'.
For example, from the same 1959 published Chrysler Master tech book linked above.
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I don't have any early GM books here, but I'll see what I can dig up.