If we dont want to face massive stuff (weapons, ammo, armors, drugs,..) inflation, system has to have somewhere its own bottleneck (hope i used correct phraze).
Cooldown is kind of one bottleneck, simple to integrate but i dont like it.
Why not try different aproach.
Level 0 resources (on any form: minerals, prefabricates, even quite damaged weapons from encounters) would be used to ger Lvl 1 resources.
Lvl 1 res (better equipment, similar to tier 1 weapons and armors) would be used to ger lvl 2 res.
Lvl 2 res .... to get lvl 3 res..
How? Imagine situation, that you have encounter (or even some solid location on world map..) where lvl 1 res. would exist. To get those res., you would need to spend, INVEST only lvl. 0 stuff (form lvl. 0 res).
Example: location.. abadoned mine full of wanamingo (or something else, ..). You would have to use lvl 0 weapons (shotguns with knockback perks, knockback melee weapons), because wanamingo are very though and you would need to spend 1000 lvl 3 ammo from avenger to kill them. But with good knockback weapons, you would only pass thru them, with good organization and luck of course. After you will bypass them, you would be able to get (mine, find, craft) lvl. 1 resources (weapons), that you would need to get lvl 2 res...
Of course, that those lvl 0, 1, 2 ... stuff would not have only this one purpose. It would be availbe to PvE, PvP, trade ... but you would have to get lower level stuff to obtain higher level.
Other idea: team (not only faction based) scavenging (it is multi players, you can find frined in NCR,...)
Hunting idea: every critter you attack is attacking you too.. I can imagine some rare critters, that if you kill them, they would have valuable resource (skin to armor, ...). But their attributes would be set that they would run away from you, if they see you. So you would have to locate them (by shit on ground), get to them from the side they dont look, then cripple them (or encircle them) and finaly, kill them and loot some resource from them.. It would need cooperation with players and it would provide very different gameplay than stay and push the fire button.