Plain and simple. .38 special looses much energy through the cylinder gap and through short barrels. Just look at .38 special out of a lever action, of course much more energy. A semi auto doesn't have a cylinder gap, it is much more energy efficient than a revolver. 9mm from a revolver with cylinder gap and perhaps 2" barrel won't give you the energy you're used to. Slightly below .38 special.
I never stated that the .38 has more energy than 9mm in the normal platforms. I stated 9mm has 20% more when bought from Winchester and 28% if bought from Corbon (btw. that is J-frame vs. full size auto, out of 4" barrels it's only 10%).
Your energy figures are slightly incorrect. 9mm +p has ca. 400 ft-lbs, not ever 500. 450 is from Corbon and that's one of the hottest +p+ loads out of all. 500 ft-lbs is .357 magnum out of 4" barrels..
And no, 9mm does not rival .45 acp. Perhaps +p or +p+ vs. the normal .45 loads. But .45 +p really offers 500 ft-lbs., a very potent round in the +p form!
Hm, let's see what Winchester does offer:
.380 85gr = 189ft-bs = 68%
.38 158gr = 278ft-lbs = 100%
9mm 147gr = 333ft-lbs = 120%
So I would say the .38 is nearer to 9mm than to .380 ;-)
Perhaps we just differ in our view. Might it be that you look at 9mm and .38 from the semi auto perspective? 115gr very high energy 9mm bullets, caliber more important than weapon in the semi auto world etc.
I take the revolver perspective: caliber doesn't matter that much as load (weakest/strongest load difference in .38 is 1:3), barrel length, I tend to heavy bullets as I am used to them etc.
I just don't like the general bashing of the .38 regardless of platform and I don't like todays underloaded .38s. They have way more potential than that, platform is all that limits if self loading for instance. Damn those alloy frame snubs.