Money can buy temporary compliance but not fundamental loyalty. The former might be enough if the timing is right, or it might be enough if tribal compliance could be made to evolve into something approaching loyalty. Tribalism is fundamentally at odds every Western ideal that an enlightened administration would want to impose on Afghanistan. I frankly do not know what a Marxist administration or the would want to do about exploiting, curbing, or even encouraging tribalism in Afghanistan.
Consider the tribalism of the Plains Indians at the time of Sitting Bull and Custer. The cultural intimacy of the tribe has extraordinary pull on the individual and it is not easily surrendered for the plastic salvation of Western civilization. Or better yet, consider the Crips and Bloods.