I think economic sustainability is the most important factor in evaluating the success of an implemented solution.
I heard from some economist (don't remember that name, sorry) that if you put a $1 in the economy and not invest in infrastructure your $ will bounce of in a black h***. But if you invest 50cents in cash and 50cents in infrastructure, training and other supplemental resources your money will multiply.
The reason he said is because people will use that 50cent cash to use the technology that you have implemented and produce some valuable substance from which they can either use for themselves and if they produce enough of that valuable substance then they will sell it to others. Hence, getting money in return and the cycle of economy will start from that bare 50cent in cash and 50cent technology.