My long experience in game say: if person not spend real money on game - not will spend newer. And its not important expensive or not.
Ok for example. Prestige price JUST ~15$ JUST! But prestige using just some hundred people from some thousands online.
Why? Just see people who play, and from where... A lot l2 gamers not working... They play 12-14h per day... They living in regions where salary JOKE size...
For example in Naia - alot people from Romania, Russia, Ukraina, Bulgaria, Grecia, Filipinos, Vietnam, Brasilia and etc... What they can pay if in this countries salary 200-300$...?
Server orientated in USA and West Europe people. If someone play for example from Vietnam and say "high price" - its not server problem, its just this people problem if start play not in right server. Want low prices - go in server for poor countries. For example Inova - orientated Russian region (where people salary very low level). And no problems.