When the French joined in we were not winning. We just weren’t losing as expected.
You’ll have to read Benjamin Franklin’s biography to see different. He was in Paris pleading on a daily basis for French help. The French didn’t want to jump in on a loosing proposition because of all the defeats we were having.
More like when they saw we wouldn’t fold like a cheap deck of cards. We didn’t actually start winning until the British began their southern campaign and after early major successes had their butts handed to them at King’s Mountain and Cowpens. In the north the contest had become a staring contest outside New York. The Brits gambled on the south being strongly Tory and they lost.