Gun Control & RKBA

I doubt the OP was making the claim that that specific model of semi-auto was the most common model userd either, only that semi-autos were. This is not true, although to be honest getting close.
Regardless of specific model arcana, the .38 specials were and still are ubiquitous, cheap and easy to maintain and load, which is the only reason they are used most often. That's why silliness like the OP's makes no sense. Street criminals have no loyalty to model or type they just want cheap and easy and, if they have maintained a few brain cells through the meth and crack and heroin haze, reliable. A few pro hitmen may be more loyal to the quieter and penetrative .22 with hot loads but your average gang-banger gets whatever he can buy and load for cheap. 9mms are getting there, but .38s were still in the lead last numbers I saw, and given the indifferent maintenance, cleaning and loading regimen of that particular echelon, probably a more sensible bet. Glock fans tout their ability to work after much abuse and little care and doubtless that's true to a point, but even though I can't shoot one worth a damn with the usual long DA pull at least, if I were, ludicrous schlock TV example though it were, forced to grab one at random when it absolutely had to go bang, the revolver it would be. I suspect the criminal element have much the same thoughts.