it's contrary to human nature. James Madison laid out the reason why we have to have a government in the most concise way.
"But what is government itself, but the greatest of all reflections on human nature? If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary. In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself. A dependence on the people is, no doubt, the primary control on the government; but experience has taught mankind the necessity of auxiliary precautions." - James Madison Federalist 51
The social contract is necessary because if it did not exist we would devolve into fiefdoms with each aristocrat sitting on billions paying for his own little army. Basically a technologically advanced form of feudalism with no governmental checks on the manor lords.