Buff everything instead of Nerfing X (why that in the end does nothing)

Wing

a game is designed around a set difficulty level or delta.

for instance everything does roughly a set amount of damage or has a set amount of health that has a slight +/- delta associated with it depending on the circumstances.

then player power is determined and balanced around this delta based on the perceived difficulty of the gameplay or style of game the developers intend to make. examples being destiny being a more classic rpg damage and difficulty scaling compared to warframe being more like and arpg scaling, in destiny even taking care of the trash mobs can be a chore and requires things like headshots or crits to deal with efficiently, where as in warframe your going to be cutting and nuking through waves of enemies often not even visually seeing all the hordes your killing, a closer example would be eso vs diablo.

so what does this have to do with buff all of y instead of nerfing the singular x? and why does in the end it mean nothing?

if y, for sake of argument necromancer, is far and away stronger then the delta of the intended game, and by that design trivialize or make content more easy, then the request is "buff everything else"
ignoring the fact that its just less time consuming and resource intensive to nerf one overperforming skill or class then figuring out how to buff the others, lets say you do instead buff all the others AND this works out flawlessly, they are all stronger, and all balanced.

however they are all more powerful then originally intended in the original difficulty curve of the game. so now the developers either have to accept that content is now easy and that's just how they design new content going foward, that they need MORE difficult content and we end up with two types of content, old easy and new hard (we see this now with dungeons because of CP) or go back and make all content more difficult.

but if they make harder content, or go back and adjust the delta of difficulty for the ENTIRE game, then the balance of power between the players, the characters, and the content, is EXACTLY where it was before necromancer was introduced. you buff everything, and therefore nothing, as its all going to play the EXACT same.

so they can either buff all the classes, buff and rescale all the content in the game
OR
nerf necromancer a little bit

the end result is the exact same gameplay, you will be just as strong regardless.

and that is why "BUFF EVERYTHING ELSE!!!" never works, it all ends up the exact same, its just the effort required to get there.