The Need for Government or Anarchy?

Mises and Friedman are in agreement "The consistent liberal is not an anarchist."
To Mises and Friedman it is a rather simple argument: How do you enforce your rules upon society to protect your property, your life, and your liberty without a government?
Mises' explained the need for government with ease:

"Life in society would be quite impossible if the people who desire its continued existence and who conduct themselves accordingly had to forgo the use of force and compulsion against those who are prepared to undermine society by their behavior. A small number of antisocial individuals, i.e., persons who are not willing or able to make the temporary sacrifices that society demands of them, could make all society impossible. Without the application of compulsion and coercion against the enemies of society, there could not be any life in society.
We call the social apparatus of compulsion and coercion that induces people to abide by the rules of life in society, the state; the rules according to which the state proceeds, law; and the organs charged with the responsibility of administering the apparatus of compulsion, government."

Their main questions is, what are the chances of everyone agreeing upon the said terms in a voluntary society with no government? What guarantees are in place to make sure that later generations do not choose against those very terms?

As much as they opposed government with the notion the market is more proficient than the government in most tasks, both intellectual greats, Mises & Friedman, conclude that life could not function without some sort of coercion, albeit a constrained coercion.

Is the market a better enforcer than the government? Can we not apply the same questions they had asked about life without a government to life with a government? What guarantees individuals agree to the terms? Let us take in mind that the market is not capable of extending its might through coercive social programs such as the government.