Why do some libertarians think that its possible to have a limited government constrained by the constitution?

What evidence is there that this could ever be a reality? The state grows as large as it can afford to be at any given time. The constitution isn't magic and it cannot stop a bullet. Throughout history states rise and inevitably collapse because the initiation of violence is no basis for a civil society and can't solve social problems in the long run. Perhaps libertarians should focus their efforts on a more sustainable alternative and quit begging their masters to relinquish their power because it will never happen. At this point too many voters have their livelihoods directly or indirectly supported by the state for there ever to be a ground swell of support for limited government.