Their number one export for decades has been electricity to India from hydroelectric. India has abused their position as the only customer Bhutan can sell to. If memory serves me, They also replaced GDP measurements with GNH (gross national happiness) and the monarch willing divested power to a democratically elected parliament. For a wealthy landlocked country with abundant hydroelectric, this was the right move. Now they need to consider how to protect their territory from future invasions. 

 Thanks for the insights!