How come?

Too many different combinations. This game is already very difficult for Bungie to balance becasue of all the different possible perk combinations. The reason why the situation is manageable is that those perks are laid on a foundation of a very limited number of base weapon archetypes. What you are talking about is basically letting people PICK their perk combinations by what is basically re-rolling.....and then allowing them to alter the weapon archetypes as well. So what everyone would basically do is keep at it until they go THE most powerful version of the weapon possible. 1. That would be a NIGHTMARE to try to manage in PVP. 2. It would also be a problem in PVE, because you'd get this WIDE variation in weapon power between those who'd have the time and resources to manufacture their own god-rolled weapons....and people who just had average load outs. The Division 1 nearly self-destructed as a game because of this. They tuned the game to "preserve the challenge" for people who basically used the game's crafting and re-calibrating system this way..... ...and what happened is that the game became unplayable for everyone else.

Not being able to change the archetype would solve all of these problems.

Would **simplify** them....not solve them.

*solve. We can already choose perks and get the best possible options relatively easily with the menagerie. Changing the archetype is a pretty cool idea, but it would be hell to balance.

No. It won’t. Because Bungie limits what perk you can combine on any given weapon, and then limits what armor-based weapon perks you can combine. All those serve to limit the power gradient between the game’s best gear and the average loadout.

All the most broken perk combinations can already be found in the game.

Then nobody played the game until year 3 because everything was nerfed and it wasn't fun. Div2 is the same way, everything is watered down and no fun.