GW KNEW he had to keep the army in tact. As long as there was a standing colonial army, there was a Revolution. Just like Grant and Lee in the US Civil War
That was precisely George Washington's strategy. Wear them down. Supplies and equipment were being brought in from England. Washington knew he couldn't defeat the British, they had more experience on the battlefield and more organized (although their supply lines weren't and it was also costly).
You both talk about the French, don't forget the Germans and the Indians that were fighting on the British side.