Imagine I get a heat-proof plastic bag or other convenient container, put a chicken in it sealling it completely and bake it. All bacterias/living thing should be dead and the food should rely inside a sterile environment, right? Could I be able to store it on my kitchen shelf and leave it there for a long period of time without spoiling it? I have a feeling it's not possible otherwise we would be using this technic for a while, but why itsn't it?
You would need to use fancy pressure canning techniques to get the entire contents of your container up to the temperatures required to kill botulism spores (et al?) that could begin to thrive later in the anaerobic environment inside. But given that prerequisite, what you describe sounds like the canned meat products that you find in the grocery store. You can certainly find canned cooked chicken meat there (near the canned cooked tuna in supermarkets near me).
As for a whole canned chicken, no, I don't see that in my area. Maybe the effort required to achieve this isn't cost effective for the consumer market. Doing it at home as you describe doesn't seem worth the trouble to me. Perhaps NASA is working on it.