In the 1970s and 80s an organization called Sarvodaya became prominent in Sri Lanka and attracted much attention in the West. Supposedly based on Theravadin and Gandhian principals, Sarvodaya ran numerous development programs in rural areas throughout Sri Lanka. The organization’s founder A. T. Aryaratna took Pali words like dana and coined new terms like shramadana, ‘the gift of labor’, in an attempt to give his concepts a Theravadin feel. Numerous books and articles have been written portraying Sarvodaya as an authentic Theravadin and home-grown model of development, rather than one derived from Western concepts. The truth is rather different. One of Sarvodaya’s goals was to try to get monks involved in village development. This met with lukewarm results. Eventually, at considerable expense, a Sarvodaya Training Institute was established with the purpose of training such monks for this role but it soon had problems with recruitment or even with keeping or motivating the few monks who did come forward, and eventually it closed down. Gombrich and Obeyesekere have given their reasons for this failure. Most young monks were just waiting to finish their education before disrobing; they were not really interested in long term commitment; some were not suited for social work; others were aware of public disapproval of monks doing social work. 
I would agree with this assessment, but I think it is only part of the story. After all, Sarvodaya not only failed to awaken the monk’s social compassion in a focused and sustained way, it failed to motivate it in lay people too.
In Joanna Macy’s glowing and idealized account of Sarvodaya she claims that monks have been known to do hard physical labor. I find this highly unlikely. The times I participated in Sarvodaya activities the other monks did little more than give short pep talks and stand on the sidelines making suggestions. As for the work itself, it seemed symbolic rather than planned to make a lasting difference to the village, and even this was constantly interrupted while the needs of the monks were catered to; ‘Would Venerable like a glass of water?’ ‘Sit here Venerable so you don’t get your robe dirty,’ ‘Venerable, it’s nearly time for your dana,’ In the late 1980s after Western donors decided to withdraw financial support from Sarvodaya so that could no longer pay full time workers, it very quickly became dormant and to the best of my knowledge has remained so since. While I think this is a tragedy I also think it was inevitable. Sarvodaya’s aims and principles have no basis in Theravadin doctrine, they have no forerunner in Theravadin history and therefore they never went deep in the hearts or minds of either monks or lay people. As soon as the salaried workers went the projects began to peter out. One must have the highest respect for Ariyaratna’s determined and genuine efforts to try to make Theravada more socially relevant and in a Mahayana country he might have succeeded. But his whole vision was so at odds with everything Theravadian that it never had a chance. And of course Sarvodaya is not the first such effort to wither under the dead hand of Theravada orthodoxy and clerical inertia.
The Mahabodhi Society was started with both a Buddhist missionary and a social service agenda in 1893 by the Westernized and Christian-influenced Anagarika Dharmapala. Generously financed by an American patron,  the society was able to build dispensaries, orphanages, vocational training and industrial schools and a seminary. But Dharmapala had constant difficulties trying to find dedicated monks to run them and by the 1940s most of the social and educational work had withered away. Today, other than commemorating past achievements, providing accommodation for Sri Lankan pilgrims in India, and fighting court cases, the Mahabodhi Society does almost nothing, even its long-running magazine has died a natural death. The Gramasamvaradhana Movement in Sri Lanka in the 1930s had a similar history. Its initial success was due to a few exceptional monks but it too soon floundered.
Even when given state support and encouragement Theravadin monks seem incapable of sustained interest or commitment. In the 1960s the Thai government launched the Thammacharik Program with the goal of bringing the country’s hill tribes into the mainstream of society. Monks were given training and the resources needed to go into remote areas to teach Buddhism. The reports on the progress of the Program make interesting reading. The monks’ idea of spreading the Dhamma consisted, as one would expect, of teaching the tribes people how to bow to them properly, how to offer food in the right way and to chant the Metta Sutta for them. They didn’t learn the language, they were not interested in making a long term commitment, they avoided hardship or inconvenience, they were not prepared to compromise on their rules and the locals were expected to change their norms to suit the monks, not the other way around. The Thammacharik Program was a failure as far as spreading Buddhism was concerned and was eventually abandoned. Christian missionaries soon moved in with their schools, basic health services and agricultural training programs etc. and today a large number of Thailand’s hill tribes are Christian. It is true however; that in recent times more monks and lay people have began expressing compassion through good works. This is a very encouraging sign but it is still in its infancy and still involves a small number of people. As soon as one says this to Western Theravadins they will immediately start reciting the names of well-known Theravadin individuals or organizations that are doing something for others. But such efforts become well-known precisely because they are so exceptional.