But because of France and Spain, the British couldn't use their full strength, land or naval due to threat to the home country.
Siege of Yorktown: 8,000 American troops + 3100 militia, 7800-8800 French Regulars + 29 Warships. leaders, George Washington, Marquis de Lafayette, Marshal Jean-Baptiste Donatien de Vimeur, comte de Rochambeau, Lieutenant Général des Armées Navales François-Joseph Paul, marquis de Grasse Tilly, comte de Grasse
Might also want to read about the Marquis de Lafayette and his contribution. I think you need to swaollow your pride and admit the Americans had a LOT of help, financially, logistically, materially, and military support.