Not arguing the past use of captured items.
Heck, we even supplied the French with the FP-45 “Liberator” so they could go out and gain better guns and gear.

But to make gathering food/ammo/etc an integral part of the supply plan? I’m not going to count on the supplies my opponents bring for my meal at the end of a fight/battle/march.

You have to start somewhere.
A kitchen knife can get you a pistol.
A pistol can get you a rifle, some ammo and maybe some grenades.
A rifle can get you……….
The skies the limit in some respects.

Look at what the Bielski’s accomplished in WWII Belarus.
Starting with essentially nothing, they became a resistance threat to the Germans.
Over a thousand people survived thanks to their ‘work’.
They had to scrounge, steal, make and buy everything, and they came close to starving many times.
Despite the Germans, as well as locals supplying them, willingly or unwillingly.

There is no guarantee of supplies, except those which you put back yourself.

Changing it around a bit, the “Doomsday Prepper” who went to jail recently.
He advertized that he and his group only stocked 6 months of food and were going to become Marauders post-SHTF to gather and gain more food/gear. He was planning to rob, steal and kill his neighbors, and said so on national TV.
The fact that he was a felon and was in possession of firearms, and again on national TV, got him thrown back in jail. But his plan was to steal food instead of storing it.

Again, I have no problem with scrounging food/gear/ammo to augment ones supplies.
But to make that an integral part of the plans, making your survival dependent on it, not a good idea.
Especially in times of “plenty” as it were.
Right now we can go down to the grocery store and get food, enough food to last a long time.
And tomorrow the prices may rise, but you will still be able to get more to add to the stockpile.
The day after that? Anybody’s guess.

But I can only count on what I put back, what I have on hand, not what I might scrounge.