Imho: because Western populations care about environmentalism and don't like to use their power to compel others, even if that would be more efficient. They can do something while not feeling bad when they restrict it in Western nations. I do believe that there's a culture thing as well, the predominantly protestant nations appear to be more eager than the catholic ones.

Projects focusing on the developing or third world will likely be regarded as colonialism, lecturing from a position of power etc, and perception has become more important than correctness or efficiency.