I have thousands of rounds of practice behind me (actually, 1000 rounds is a fairly typical, or even slightly slow, month), was rated Expert in Navy and Army qualification courses, shoot IDPA twice a month, and do a lot of shooting both at the LGS range and in my back pasture.
I don't consider my skills to be particularly poor.
That said, I still prefer more over less, within reason. The 1911 is a good middle point for me, in that I shoot the platform very well, including one-handed and weak-handed; it fires an effective round; and it is faster to reload than are my revolvers.
It lacks the capacity of some of my 9mm pistols, but what it lacks in capacity it makes up for in my ability to put accurate fire on target, quickly.
Shooting with formal stances and two-handed holds, I am faster with a 9mm. Through experimentation with one-handed shooting while moving or somewhat off-balance, I do better with the 1911. Since I believe in planning based more on worst case than on best case (hey, it's better when surprises are pleasant, isn't it?), I think it's important to be able to shoot with one hand, and whichever hand is still functional or not otherwise occupied.
I shoot K frames about equally well, but have more rounds and faster reloads with the 1911.
So, my points?
1) Don't assume that people who like a capacity advantage are necessarily poor shots.
2) Don't assume that people who like a capacity advantage believe in spray and pray.
3) Don't assume that people who like capacity, consider capacity alone to be a deciding factor.
4) Choosing the right handgun and carry package should involve more than just comparing relative capacity; but, capacity is still a factor that should be considered.