The original 13 colonies would have made a go at it here in America, more or less alone. They tried for a short time. But realized they needed each other. And our system worked well for us. Our only major failure, was that we never addressed the slave question and left it for a future generation to deal with.
I think a lot of people, perhaps you, have this thought that a step towards unification is a step towards progress. And all progress is positive. I don't agree. Progress for the sake of progress is like spinning the bottle and deciding to move to where that bottle stops. It's not really progressive, and can often be regressive. Because eventually you start ignoring other factors if your main goal is simply moving forward and attempting the new.