You're looking for a "life simulation" rather than a game. Nothing wrong with the concept, but to take a game and try to make it into something else is just going to frustrate you. There's a lot in Skyrim that you have to have a healthy suspension of disbelief to enjoy. I beleive my character is eating... resting... and yes, using the bathroom, even though I don't engage it in any of these activities. Forcing me to hit keys to do these things would make skyrim feel like one of those virtual pets that were so popular for a few weeks a few years ago.
You say "life simulation" like it is a bad thing. Sure, no one wants to take a leak or a dump in a video game. That's just gross. But Skyrim already has food and drink and beds you can use. What is wrong with implementing, as an optional feature, a realistic hunger/fatigue system? This type of mod has been out for Oblivion for years and a lot of people use it and enjoy it.
But for the majority of Skyrim players who play on a console and cannot use mods, there is no option for a realistic hunger/fatigue system unless Bethesda implements it. If it is an optional feature that has to be switched on through the options menu it won't interfere with folks like you who don't want it but it help other folks enjoy roleplaying more.