For those who have modding experience/game creating backgrounds what other than time and resources could prevent it from happening for the new systems?
Why would you need a toggle switch.
Just look at "Fallout: New Vegas".
I think it was called "hardcoe Mode" but you had to manage your hydration and food and ammo had weight, etc...
Or are you thinking of something like "Freelancer's" Mod Manager that would apply and remove any MOD you had for the game?