Shortest answer: there's nothing special in human biology, you could totally make it
Short answer: Bachelor chow!
I would totally buy this stuff if they made it. The closest I have now to bland, flavorless, zero thought/effort food is Wheaties.
longer answer:
Seriously though, dogfood for humans wouldn't be that hard to make. If you just took everything from the RDI guidelines (the Recommended Daily Intake from which they calculate the percentages you find on food labels) and mashed it all together into a thick brown paste you would get all of the macro and micro nutrients that you theoretically require. Precise proportions are irrelevant because:
a) everyone is a little different, and
b) to some extent, our bodies are able to fine tune our digestive tracts to fit our specific diets (presumably this tuning would occur even faster if you ate the exact same thing for every meal). You're a mammalian omnivore. Enjoy it!
You probably shouldn't try to live on something like this for the rest of your life, since there's plenty of research suggesting that there are other micronutrients, such as phytocompounds (i.e. plant stuffs), that are poorly understood but may be beneficial to humans. One thing to note here is that any health claims about any antioxidant that is not on the list of essential vitamins (vitamin C is an antioxidant on the list) are almost certainly bunk and/or hokum.
The upshot is that you would only need, at most, utterly minuscule quantities of these miscellaneous micronutrients. You would be fine(ish) for at least a few months. For related reasons, your statement:
The composition is also known for human babies. This is manufactured as "baby formula". Everything baby's organism needs to be healthy (and to grow).
is largely correct but somewhat flawed. While it is true that many babies are raised solely on formula and subsequently turn out just fine, there are some things that you can only get from mother's milk. For example, the mother passes on components of her own immune system to her baby through her milk, which then help to strengthen the baby's own immune system. These are the kind of subtle but useful compounds which are encountered in a "natural" diet but which could never realistically be included in people chow.
