The British didn’t really lose the Revolutionary War so much as they failed to win. The Americans, on the other hand, didn’t really win so much as they failed to lose.. How is this possible?
This is possible because the British needed to actually go out and win the war while all the Americans had to do was avoid losing. The Americans avoided losing, the British didn't win.
The British needed to outright win the war. They needed to completely conquer the Americans and make them willing to come back and be a part of the British empire again. By contrast, all the Americans needed to do was to avoid losing. They just needed to hold on long enough to make the British get tired of the war and give up.
This is exactly what happened. The Americans did not drive the British armies out of the colonies. At the end of the war, the British still held major cities like New York and Charleston. It is doubtful that the Continental Army could ever have completely defeated the British. However, the British got tired of the fight and decided it wasn't worth it. In that way, the Americans won simply by not losing and the British lost by not winning.