Thats the thing though, atleast in my experience the survival/upkeep layer of 3/NV was extremely un-challenging, and although I appreciate it for roleplaying I can see why its gone because for many people it was more of a chore than a challenge.
Have you ever played the Stalker mod Misery? That is a example of how you can make a extremely challenging system of upkeep/survival elements, and also turn it into a very niche game that appeals to very few.
The reason Bethesda has been able to make so many millions is that their games appeal to so many different kinds of players. If we were to make a murderous difficulty level with survival stuff, it would drive off people who may be more interested in roleplaying or choices and consequences. Or drive off people interested in exploration, or any other kinds of players. Bethesda puts a lot of thought into their game, and people don't seem to realize that most everything we see is the result of years of intensive development and heavy thought.