In the Declaration of Independence, the statement was made of repeated times the colonists petitioned the King to redress their grievances ... only to be rebuffed. Armed revolution came when the British fired the first shots at Lexington and Concord - the shot heard around the world.
All other revolutions had terrible consequences ... the Russian Revolution (1917), China’s cultural revolution (1960s), ... the Iranian Revolution (1979) ...
Some folks like to believe that our founders were itching for a fight and nothing could be further from the truth. As you said, decades of negotiations failed.
Testimony given by Ben Franklin before the house of commons a full decade before the opening shots. He warned them that they were going to drive the colonies to war.
http://www.bartleby.com/268/8/10.html