The correct answer to this open question is the following.
What led the British army to make tactical mistakes that finally led them to lose the revolutionary was that they lacked respect for Patriot soldiers and the entire Continental Army.
That lack of respect made British troops to have an overconfident attitude and made the wrong formation choices to fight the American troops. Yes, the British were more prepared and have enough supplies to fight the Revolutionary War. But the Americans were defending their territory and had the hunger for liberty, to be independent of the English crown. Furthermore, the US troops received special training by a Prussian Officer when they were at Valley Forge and also receive the help of the French troops to win the war.