Tourism is actually under 5% of the Indonesian GDP. While personally, I'd love to dispense with the VOA system just so I get a fair shot at getting a good place in the immigration queues, I do understand that why Indonesia feels obligated to charge US$10/25 for a visa when it costs a bare minimum of US$100 for an Indonesian to apply (way before arrival, non-refundable even if denied) for an American visa.