9mm has been around for a long time and lots of supply/demand. 380 has never been as popular until recently. Thats why 9mm has always been easier to find and cheaper. If you are over penetrating with a 9mm you are using the wrong ammo. A defense round should expand (mushroom) quickly. Which provides more stopping power and decreases the likelihood of over penetration.

One of our friends just got a SR9c about 2 months ago and we tried it. We both liked it a lot. Didn't think the recoil was that bad at all.
The recoil isnt bad at all. And really its no more then the P944 .40 cal. It just feels a bit sharper. Mostly because the SR9c is much smaller and lighter (polymer frame vs aluminum) then the .40. Its much less then with an LCP .380 which hurts my hand when I fire one.

A .22 can kill just as well as any other round. Shot placement is much more important though and doesnt have the immediate stopping power of a larger caliber. We recently had twins try to kill themselves at the shooting range across the street from me in a suicide pact. Both shot themselves in the head with .22s they rented. One died immediately, the other lived and walked out of the hospital about a week later.