There isn't any one answer to this questions because there are a wide range of Buddhist communities, each one might have a slightly different model of economic sustainability. Some are self-sustaining, some supported by the community others might receive some form of grant or charitable funding. You need to provide a more specific example.
To provide military support for missions, and later settlements, until these communities could support themselves! ;-)
Transition Networks provide support within communities. They aspire to inspire and encourage and help to train communities to help themselves for the better.
For some, it's for fun. But for most, it's in order to support themselves, their families, their charities and their communities.
For the same reason that lay Christians support monasteries. Not everyone is suited to a life of devotion, but most people recognize that spiritual seekers give back to their communities in myriad ways which should be supported.
Planes are essential to military operations. They transport troops, cargo, supplies, etc. all across the globe and provide support for combat operations both on the ground and the in the air in offensive and defensive operations.
Medical communities, support groups, therapy / therapists communities, and local / related family and friends.
they support bymoving \
Usually, old people were cared for by their families if they could not provide for themselves. If they could not provide for themselves, they were cared for by the Church, possibly in monasteries, or by their communities. Since charity was an important part of Christian life, they were not usually completely without support.
Emergency support functions operate under the Operations Section Chief in the Incident Command System when activated for emergency response operations.
people live in communities.................................
To support emergency management operations.
The Janjaweed, a militia group in Sudan, primarily support themselves through various means, including looting, extortion, and illegal trade, particularly in cattle and agricultural goods. They have also been reported to receive support from the Sudanese government, which has provided them with weapons and resources in exchange for their role in combating rebel groups. Additionally, they may engage in criminal activities and exploit local populations to sustain their operations.