There are three connected reasons why the British failed when they tried to use a “southern strategy” in the Revolutionary War. This strategy was based on the idea that there were many Loyalists in the South who would be helpful to the British. This was a miscalculation and the British actions in the South made things even worse.
To begin with, there were not as many Loyalists willing to fight as the British might have thought. One reason for this was a fear of retaliation. It could be dangerous to fight for one side or the other in this war as the other side might kill your family. This meant that more people preferred to stay neutral if they could.
The second factor was the American strategy in the South. The Americans did not engage in many pitched battles in this region. Here, more than in the North, the war was more like a guerrilla war. The American forces under General Nathanael Greene used hit and run tactics and forced the British to chase them across the countryside. This was a problem for the British in part because it depleted their supplies and their manpower without really giving them a chance to strike a decisive blow.
Finally, the guerrilla strategy and the British response to it reduced support for the British even further. As the British chased the Americans through the countryside, they tended to “live off the land.” This meant that they were taking supplies from farmers. When they did this, they tended to make new enemies as people who might once have been neutral came to have a better reason to want to work against the British.
In these ways, the British strategy failed because they overestimated the amount of support they would get from Loyalists.