If you can't kill a hog with a .223, the problem is the nut behind the stock...
.22 lr will kill a hog, lots of folks use the .22 magnum or .17 HMR too.
I've killed, or seen killed about the same number of hogs with the .223 and the .300 BLK (as well as bigger rounds like the .243, .270 and .30-06). I've recovered more shot with the .300 blk. The ones hit with the .223 don't go very far, but even 50-100 yards is tough to find in the dark with little to no blood trail.
I killed one with my .40 S+W Glock, didn't find him till the next day either. Actually heard him thrashing around in a thicket about 25 yards away, pretty sure that was as he was dying, but I didn't really feel like crawling in there looking for him.
So while I agree .223 will kill hogs just fine with the right bullet, something bigger will allow you to recover more hogs.