You are plain wrong about head shots. They are for snipers, not homeowners. The standard LO training discourages headshots because they are so difficult. I'll trust their opinion on this. Also, .22s, .25s, .32s are better than nothing but there are reasons why our military and police don't carry them. The .38 revolver is still part of the USA arsenal.
The main reason the .38 was used had more to do with tradition than effectiveness, although it is pretty effective.
I suspect the number of agencies which issue the .38 special are very very rare nowadays.
As a matter of fact the .32 has been used by European PD's for nearly a century. It has also been heavily used by the military.
That doesn't mean that I think either the .32 or .38 special are ideal. If I had my choice of pistol, and knew I were going to be in a gunfight then I would probably choose an 8 shot .357. I would be perfectly content to trust my life to a 9mm, .40S&W, .45ACP etc. tho.
If I were facing multiple unarmed people I would even feel reasonably comfortable with a .22.