@INSURGENT Skirmisher Hobby wise, you have a case, which is GW exists as the big fish in a small pound.
As far as reality goes you made a terrible case (like the worst case ever), still are (infact your examples are just getting worst, no one in real life is going to recruit a cannibal knowingly, you kill cannibles right off the bat if you can't jail them cause you can't trust people who may see you as a possible meal in any situtation, particularly in a wasteland of survival, what heck are you thinking?😆) and are still telling me I should take your word for it on how this works like your some expert who spent thier whole live researching it when its clear you aren't as I have already spent a good chunk of my life with someone who actually researched these very topics to death (I have even made some of the same arguements you did and got shot down). So your getting an Essay rant.
The folks with autocads will turn around and use said autocads to make more autocads to trade around, after awhile every town, outpost, base, wandering hoard and if they still exist bandit hidout will have at least one, probably 3 with operaters, even on the fringes.
And I say this because we already have people on the "fringes" doing that exact thing right now in places like Afghanistan, they have AK74s (not 47s, 74s) alongside older boltaction rifles and trashbash rapid fire guns as well as newer things, they didn't just loot it all in raids either, they made some of it and you don't see any of them or anyone else in the modern fringe world using crossbows or spears makeshift or otherwise in actual human to human combat which if it was going to happen for your reason would already be widely reported and talked about here on this forum, (like IRL they only show up in the first/second world urban areas during riots or in the hands of bank robber nowdays). The only blackpowder weapons you really see are one off explosives using soda cans,etc. as shells not muskets which again only really show up in the first would and generally more complex or rather old finnicky (I mean the last "musket" I have heard of used was the elctrolock used to kill the former prime minister of Japan).
Also, historically the "massive deprivations on the bottom and on the fringes of civilization" and "vanishing resources" does not exist the way you think it does, outside of poor island forestry managment, that all seems to normally happpen due to population drops due to cultural reasons which won't affect weaponry tech as far as personal arms go. In fact "fringes of civilization" is more like "catch up to current best development" cause they tend to get all the trash and second hand items from the "rich" and in a setting where space colonization is a thing "vanishing resources" seem unlikely except maybe via population drops due to lack of personel to fix and process stuff. (Also in real life poor places tend get large populations fast and if they are not run by complete idiots these populations turn into work forces and after a few decades they become economic power houses, this what happend to Inda and China that where fringe but are now important cogs in the world economy).
Also in a "collapese" there likely won't be that many if any large rootless raider bands after the first decade or two cause the farming and herding communities with better logistics will have killed them all off (they are dead men walking from day 1, okay thats just reality since the raider's chances get worse each raid and if they go in with the outdated outproformed arsenal your wanting they will die on the first to second raid, apoc raiders who make bank will be ex army/law enforcement or gangers ie folks who already have good guns before the collapese and the town dewllers will end up looting thier dead bodies at some point just because of the numbers are against raider, Mad Max just isn't going to happen okay!)
As time goes on it will be even less likely that fringe people will be bringing the middle ages back to life like some bad postapoc novel. Heck realistically, by the 41st, forget lasguns (which by the way would likely be even easier to make than AKs if we knew how), I would expect the typical "raider gang" on the "fringe of sociaty" to have something more advanced than GW lore has envisioned them to have, like bio/nanomechanical "guns" that shoot seeds that use the now dead target as a seed bed to grow trees that grow more of said guns. And yes I expect that level at least by then even with the chaos gods, dark age of technoligy and other nonsense, 40k just isn't a good guidline for reality or tech devolpment (it doesn't even make sense in setting, they clearly just chose 40,000 A.D. cause it looked cool on book covers 😆).
Likewise if you ever come to my house, somhow kidnap me and drop me in the woods as you suggest, given my esitmated of your budget for this, ranger stations with WIFI will be in the woods you drop me at if not the roadside gas station and the first email you will get after a 5 hour hike if I am not in a forgiving mood will be about how I will find you and get my revenge😆. Oh and by the way most of the 3rd world has better wifi than the USA last I checked which I admit was years ago now (so probably even better now), so don't try "but in ..." they have better wifi than here. Outside some small hard to get to pockets the wildness has been tamed buddy, and by the real 41 millium this will be true of any world humans are on for more than a century, GW like most people are bad at thinking that far ahead since they don't even know half of whats going on now or why.
Also if I ever cast an iron spear,etc. it will purely be for hobby reasons or to sell on etsy cause honestly there just isn't a good reason to make them anymore beyond those two (to make a real survial spear you harden a light pointy stick over a fire at particular distance, anything else is wasting resources you should be using elsewhere, cause honestly hunting is the only good reason to make spears in a survival situtation since throwing rocks is smarter in a fight than getting close or giving your enemy a free weapon if you miss).
The only real arguement you have for doing scavangers the way you want, WHICH IS BEST ONE BTW AND YOU SHOULD STICK WITH, is that Hollywood and GW are making all the same remarkably bad assumptions you are, and personally I think they are not forgivable on this issue either and well past needing a good kick in the pants over it.