Well, there is a limit to suspension of disbelief, but it's not that low.
Honestly, when I got that quest to find the Bakers, I spent 5 hours doing so, on the side annihilating the Iron heads because I suspected they might be there, all without a promise of reward.
I sure didn't do it for money, but out of curiosity and to help some people, like the helpful person I am. That I still get way too much money is something I definitely agree on, and there needs to be a balance found given the abstraction that we don't need to pay for food and wounds heal within minutes. This is not the matter of this thread, though, and I'm sure Styg knows of it.
And even if it's not perfect, I still play the game, I just think certain suggestions would make it worse. If we had a magical bag of holding, whatever, really.
Or a drone that picks up stuff and sells it to the nearest junk merchant.
I wouldn't even be bothered by merchants buying excess at 10% the value, because why wouldn't they?
But being able to carry supplies for an army on your lonesome, that's just something I believe I need to stave off while I can. I believe that picking up only what you need is a sort of game mechanic, and the biggest problem is that the rest doesn't disappear.
As for what shops give: I consistently have never found armour even remotely as good as what I can craft on any merchant after I've reached around level 10, on any character in a good year or so. Maybe just my luck?