The Continental Army had two major drawbacks at the start of the war. The first being a severe lack of manpower and the other being a supply shortage. Not only did they have a shortage of weapons and ammo they also had a shortage of basic blankets and food. The little army they had they could not fully equip due to a lack of money but also because of other things.
The last one. During the crusades, different foods and such were found, different goods were unlocked to europe, and different mathematic and scientific ideas were brought back as well.