This is so easy to solve. I don't know why they are making band-aid fixes when all they have to do is adjust the weight of an items chance of appearing in the trader on any given reset against either the current day it resets, or the player's gamestage upon reset. The main downside to utilizing gamestage for this though would be a newbie joining your party and being there upon reset would nerf your total computed gamestage, so perhaps the day would be more relevant. For instance, a Q6 AK-47 is far more likely to appear in the trader on day 31 than it is on day 1. We have to take into consideration that the very existence of traders is a bit of a simulation of there being other survivors out there, though unseen to us, and they would be trading higher value stuff later on vs. right off the bat. This would make those random and rare high quality or advanced tech finds at the trader much more exciting early on.
The second step would be to do a reduction in the number of guns we find. At least a 75% reduction would be needed to make finding a gun actually feel like an accomplishment because right now by day 7, you can honestly just throw the guns at the blood horde and probably have plenty left over at daybreak. The second part of that equation would be to increase the value of the guns dramatically. Make finding one create a decision a player has to make: "Do I want to sell this gun that could help me survive for the Dukes to buy that awesome item I saw on the trader, or do I keep it and use it because I only have a wooden bow otherwise?" This creates a feeling of variable playstyle because someone who is more like to use bows over guns won't have much problem making that decision if there is a compound bow at the trader to buy, whereas someone who prefers firearms will have to go with their instinct either way.
The next step would be to normalize the prices of materials to be more consistent with their actual usefulness. Guns are generally going to be worth more than mods, which would generally be worth more than tools, which would generally be worth more than forged iron/steel, which would be generally worth more than wood and scrap iron. This system is already in place, but there are some inconsistencies that throw the whole pricing system out of whack.
Finally, make the quests actually worth doing. Put potential rewards in there that will entice people to do them for the chance to get the more rare items in the game, for instance certain mods, maybe crafting stations early on, higher quality weapons than you would typically find at your level, good armor pieces i.e. steel and military, power tools, and maybe even vehicle parts. Honestly, anything better than the current typical selection would be an improvement and then they could just balance from there.
Once all that is said and done, the economy of a game should be stable, people haven't twinked the hell out at level 20, the game stays challenging until later meta, and your player base generally has a more fun experience finding and trading for the items they need or want.
