Why wasn't the 440 available with a 4 spd after 1972?

[Kern Dog]

This was something I first read quite awhile ago. I thought it was common knowledge. Guess not. I don't have any of my literature with me, but did a few google searches to try to find a credible source. I came up dry. I rember coming across this info in the shop recently as well, and read it out to my dad, who owned a 74 400HP 4 speed back in the day, but I have no clue what I was reading at the time. I'll try to find it.

The same limitations hit Chevrolet and Pontiac performance cars in the later 70s. The Z28s were auto only from 77 until the new Camaro of 1982.
The reasoning that I see is that MOST people that drive automatics let the trans shift for itself 99% of the time. The engine revs up, upshifts, revs up, up shifts...
A manual trans does idle higher in neutral which is where it rests at stoplights. During operation, the engine revs up, then down during shifts, then up when the next gear is ingaged, etc. An engine in a manual trans car revs all over the place. All the rev up/down puts out more smog compared to the simply function of the auto trans.