Artemis
First time out of the vault

Bethesda is really just concern with the shooter gameplay when it comes to Fallout, so lore and roleplaying take a back seat and whilst I agree that they should've given PA later and made fusion cores rarer but last longer, Bethesda probably did what they thought was right and, understandably for once, left this kind of tweaking issue to modders
I came to the Fallout because of the lore and post-apocalyptic atmosphere. You can simply say that Bethesda just want to milk the money from the well known name, creating mass aka Call of Duty garbage.
First thing first, do you want to balance the game? Start with the Fusion Core, right now it's cheap, change the prize from 400` to 10000 caps, it's pre-war tech, it need to be expensive and also limited on the wasteland.
But it's one thing that Bethesda don't understand, for example, RadAway cost in Fallout 1, 2 and Tactics 500 caps, while Fallout 3 - 20, Fallout 4 - 80 caps. So I won't even start on the Power Armor cheap prices.