As someone who studied American history, this point of view always irks me a little bit. The reality of it is that all of the assumptions that America would have lost without French support is trying to prove a counterfactual. There are a lot of reasons to think that it would not have been so. Every southern campaign that the British had tried to pull off was a disaster. The cost to the British crown of maintaining and continuing the war was ruinous. there were many near disasters that the British just barely avoided. Washington’s position at Monmouth was set up to be decisive and Lee’s disasterous commands there played a huge role in continuing the war. Cowpens and Kings Mountain denied the British their different strategic goals. Knox managed to trap the British under the threat of guns at Boston and it was considered a miracle at the time that the British were able to evacuate to Canada. Their luck ran out at Yorktown.

Furthermore, Washington understood what most of his contemporaries did not. Simply by having an army in the Field, he denied legitimacy to the British. Washington and his generals laid out strategies that would one by one eliminate British armies in the field. To borrow a concept from the navy theoreticians Washington had an army in being. The British could not achieve their goals without the utter destruction of Washington’s army and could not maintain the armies for long periods of time. The British had to win - all Washington had to do is not loose.

At the same time, political will to continue the war would eventually run out for the British. They only had one way to win, and very many ways to loose. The fact that it was Yorktown and not Monmouth has to do with the differences between Lafayette and Charles Lee.

But let’s ignore all of that - I think at some point the colonies would have gone down the same path that the French eventually went down - a levee en masse. I suspect running into a large well armed colonial mass conscription army would have ended things very quickly.

Anyways - the French are important to the story - but it’s like claiming that American won World War I.