If you focus only on guns and ammo, you are not prepared. If you focus only on stockpiling food, you are not prepared. If your focus is too narrow on anything, you are not prepared.
Prepping means you are trying to be ready for whatever comes. You don't know if it will be a xombie apocalypse or just a supply chain collapse. You have to be ready for either one-- and both at the same time. You have to be ready for a failure of anything you need for survival, without regard to "why"-- just that it is happening.
You can't foresee everything that might cause there to be no food available to buy, but you can do things to make sure you'll be OK. You can't predict what might cause hordes of predatory creatures to swarm your property, but you can be ready to defend against them, whoever and whyever they are there. You can't know for sure why there's no electricity in the grid, but you can make sure it's not a problem for you.
Prepping is the responsible thing to do. If you are prepared you will not be a burden to society. You won't join the marauding hordes. You won't be begging for limited handouts. Don't be a xombie; be a prepper. Be responsible. Be ready for whatever comes.