I would bet that Bethesda looked at it and realized that to do it right, where it made sense and actually added something meaningful to the FO world and game play...well...the decided it wasn't worth the effort.
It would have been an embarrassment for them to turn in something similar to what Obsidian did in NV...and they saw that.
They know people wanted something hardcoe as it was all over every forum that had anything to do with FO4...but they chose not to add it for whatever reason.
I'm okay with that because I'm in love with what they gave me. I'm a very satisfied customer who doesn't need more. I create my own hardcoe Mode that far outdoes anything that could ever be coded in the game.