You would need an enormous amount of energy to achieve 0 K (-273 °C). See the system here is the atmosphere so you can think about the average outside temperature as the “state of least energy”. So you actually need to use a lot of energy to achieve that because you are going way further (although in the other direction- negative temps). Our system is earth, so 0K ain’t easy chief - check quantum computing (we need almost 0 K to work and those are huuuuge resource intensive machines). If you were in between the emptiness of galaxies, then that would be indeed the “normal default” which entropy would “go towards “. Basically, “our” entropy has a different temperature goal, because we are the system that is fed and bound to the sun. I can’t explain better because I also have limited knowledge, just the basics, sorry. Also the “” is to explain better, do not quote those as scientific.