I'm going to assume that "by following nature's models" the question is referencing the sort of thing that the political thinker John Locke called "the state of nature." Locke believed that human beings, in their natural state, can live reasonably successful lives with one another. They would be following "nature's model" in the sense of living like a community of apes or other social animals, without needing any formal government. However, Locke also believed that we can improve life together as a society if we construct governments that accentuate the positives and police the negatives.
Think of it this way: A bunch of kids on a playground can have a pretty decent game of basketball without having an official rule book or a referee. But the quality of the game can be improved even more with official rules and someone to officiate those rules. Plus, then you won't get into some endless argument over whether this (or that) was (or wasn't) a foul. The referee (the government) makes the call.
So while a sort of "state of nature" model can be workable, to a degree, most political thinkers (like Locke) have thought that planning how we will live together in an organized way is a better approach.
(We'll leave the dedicated anarchists out of the picture for now -- that would be a different question!)
