This is true. But the British error here was in not pursuing Washington and destroying his army when they had the chance. The French, Holland and Spanish allegencies were more those countries being anti-British than being pro American colonies. Alliences that the Confederacy was not able to make even after 4 years of war.
"The North didn't overwhelm the South with numbers, if that was the case they would have won the war in the first weeks. The area was even too large for the armies of the North to control and in fact they never controlled major areas of the South until the surrender."
This is true also, but when they did move through an area they left it unable to support the Southern war effort. Sherman march through Georgia to the Sea and Sheridan in the Valley for example, were not armies of occupation but were no less decisive in their impact. This had the same effect of dening the area as support for the Southern Army without the need for costly occupation. When you burn down a corn crop you usually cain't grow another crop until next year. Your Army has to be large enough to protect that corn crop. A mobile force intended to avoid heavy combat with a larger enemy does not defend territory and thereby that same corn crop.
Again Lee's army was in fact smaller and more effective and mobile than the Union army that it opposed. He won many battles. But he never did one thing. He never defeated the ENTIRE Union army at any one time. Even at his greatest victories like the Seven Days Battle and Chancellorsville the Union Army always had reserves. The Union armies defeats in these cases was only in the will to continue those battles not in their ability to continue the fighting.
That was the only REAL hope that the Confederacy ever had to win the war was to defeat the WILL of the Northern people to continue this War. To make the war so bloody in invading the South that the Northern people would grow tired of the killing. They almost achieved that in 1862 and 1863. But once the northern tactics changed with the injection of U.S. Colored Troops regiment and thereby lessening of the impact of casualities on the Northern homefront the war was lost to the South.