I remember someone posting, a while back, an article that was critical of the US approach to the insurgency while congratulating the British for their "soft touch", what happened?
What happened was they completed their mission , they got on with the locals , got them set up and handed over , that was the mission wasn't it .
Just because America is only just getting started you cannot blame the British for having finished already .

This just means that more Americans will be forced to try and pick up the slack once the British abdicate their responsibilities...
The British are abdicating nothing , they did their job .
If America is years behind schedule with their job then that is Americas fault .