I had never thought of the great nineteenth-century Swiss historian Jacob Burckhardt https://en.wikipedia.org/wiki/Jacob_Burckhardt as an allohistorian but here he has some thoughts on a failed American Revolution:
"To be sure, without foreign aid the Americans would initially have been defeated, but hardly for long. And then, the very fact that they found and accepted such foreign aid is a characteristic of people such as they were...
"Without French aid and the European naval war North America would certainly have been subjugated. Thereupon the whole political and economic life of England would have had to be oriented toward the permanent suppression of America. England would have become a sort of military state. However, the French Revolution, which would have come anyway, probably would have induced America to rebel again, but presumably so soon that England would have had to take a stand long before 1793 and join the Coalition. Anyway, in England itself the military state would have had to defend itself against a revolution. The America (United States) of 1783 had only one and a half times the population of New York today. It surely had no inkling of its future reciprocal relations with Europe, although people must have known [247] immediately that the successful revolt had a moral meaning for Europe generally. And this state had inscribed into its founding documents the “pursuit of happiness” as an aim of the life of peoples..." http://oll.libertyfund.org/titles/burckhardt-judgments-on-history-and-historians/simple
"To be sure, without foreign aid the Americans would initially have been defeated, but hardly for long. And then, the very fact that they found and accepted such foreign aid is a characteristic of people such as they were...
"Without French aid and the European naval war North America would certainly have been subjugated. Thereupon the whole political and economic life of England would have had to be oriented toward the permanent suppression of America. England would have become a sort of military state. However, the French Revolution, which would have come anyway, probably would have induced America to rebel again, but presumably so soon that England would have had to take a stand long before 1793 and join the Coalition. Anyway, in England itself the military state would have had to defend itself against a revolution. The America (United States) of 1783 had only one and a half times the population of New York today. It surely had no inkling of its future reciprocal relations with Europe, although people must have known [247] immediately that the successful revolt had a moral meaning for Europe generally. And this state had inscribed into its founding documents the “pursuit of happiness” as an aim of the life of peoples..." http://oll.libertyfund.org/titles/burckhardt-judgments-on-history-and-historians/simple