Yep, no doubt. Ammo availability will trump esoteric ballistic advantage by far.
There is so much that is unrealistic in the article that I feel I must say a few words.
1st Home defense in normal times. It is wise to have a weapon that uses ammunition that you have a large store of. I like 9mm because it is effective, safe and cheap. My wife likes 38 because it is effective and cheap. Because the 38 special ammo actually has a larger charge than the 9mm I am afraid that if I ever have to shoot someone the round would go through a person and injure someone else so I like the slightly less powerful 9mm.
2nd S#!t hits the fan world. If the world falls apart then it doesn’t make much difference which ammo is cheaper or easier to get, you will only be able to have what you have. There is no way I will be using ammo for barter I will be keeping all I have and looking for more.
Home defense in a world gone to Hell in a hand basket is a little different situation. Long range shooting could be very important. I’m not rich, I’m not poor but I don’t want to spend my money on something that I will not be ableto keep in good repair, therefore a military hardened weapon would be the best choice, something that can take a lot of abuse. I love the AK or varieties of them that are still used in many military’s all over the world. However they are not really long range, perhaps a good 100 yards top for me but the Russians made a wonder weapon a hundred years ago that can still be had brand new and never used. The Mosin-Nagant is a most wonderful long gun. If you need to shoot at 1000 yards I can’t think of a better gun to do it. I have a couple and they are straight shooters at very long distances.
So my conclusion here. Don’t have a large variety of weapons that use a lot of different ammo sizes. Stock a lot of ammo, not to barter but to have if you need it. Learn to shoot well, make sure your kids and grand kids know how to shoot well. Practice, practice and then practice some more. Then, carry. Carry all the time. We never know what will happen tomorrow, probably the same as happened today but just incase the world blows up be prepared.