Not entirely my period, but never mind. It becomes a matter of which of the British or the Americans give up the struggle first. I don’t know so much about the American side, but on the British side, the war had, in a number of respects, similarities with the Vietnam War.
It was unpopular among the political classes, and there was significant minority sympathy for the American rebels. You had, for example, the likes of Thomas Paine arguing strongly that without the loyalty of the colonists, it was futile trying to rule a colony. He argued from the point of view of Rights. Others were more pragmatic in their opposition to the war, arguing that keeping the colonies would require constant deployment of troops, which would be far more expensive than anything that could be gained.
It was unpopular among a significant minority proportion of the army which viewed its role as protecting British subjects from foreigners, not imposing will on reluctant subjects. This was a minority view, but it was one reason was a higher proportion of German troops than might be expected were deployed; the Hessians had no real problem with the idea of pointing guns at British subjects.
It was deeply unpopular amongst the mercantile class, who were pissed off that trade was being disrupted, and the general view was that the USA would never be as economically important as the Caribbean islands.
The longer the war goes on, the more unpopular it becomes, and unless it is resolved, there will come a point at which the Whigs take over from the Tories, and put an end to the expense. So the question comes as to who sticks it out longest.