The EPA evaluation process is required to ignore external costs; they may not be a factor in any decision. It does not matter to the EPA how much the requirement costs of if it makes economic sense.
I do not know that a capacitor run motor would be any more efficient, and I have never seen one that small.
They make miniature capacitor motors as small as you want to pay for it, and ive seen ones that are around 60mm diameter 40mm thick and they have a shaft power rating of 7 watts at 1400rpm.. 400rpm of slip.
I would speculate they would not be more efficient enough to pay for the second winding and the capacitor, when the equivalent additional cost could simply make a shaded pole motor large (and run it at a lower flux density), or make the fan blades more efficient.
The epa does not give a shit if the equipment will ever pay for itself, because they, along with the majority of folks on this forum, do not understand that money and energy are essentially the same thing.
So the present narrative of we need to reduce energy consumption is the hill that society may die on..regardless the cost, human or otherwise