The question must be asked, "Why didn't they disband?"
We know what happened here. Early into the six-month encampment, there was hunger, disease, and despair. Raw weather stung and numbed the soldiers. Empty stomachs were common. Cries of "beef" echoed throughout the camp. The future promised only more desperation and starvation.
Some couldn't take the cold, hunger, and uncertainty any longer. There were dozens of desertions. Disease debilitated. Death descended in droves.
But by February the weather eased somewhat — moving from brutal to merely miserable. In March, General Nathanael Greene was appointed head of the dismal Commissary Department and magically food and supplies started to trickle in. By April, Baron von Steuben, a quirky mercenary who was not really a baron, began to magically transform threadbare troops into a fighting force. Also in April, the Conway Cabal, a plot to remove George Washington from power, was quashed for good. May, brought news of the French Alliance, and with it the military and financial support of France.
On June 19, 1778, exactly six months after they Americans arrived, a new army anxious to fight the British streamed out of Valley Forge toward New Jersey. They had been transformed from Rebel into a Mature Army.