simple: volunteer agency's were complaining that volunteers were never volunteering. Hence the change to "business visa" it gives you a year to get your biz sorted inorder to stay long-term and pay them annual or monthly visa fees.
it's not "encourage" it's the literal fabric of the infrastructure. The elite visa is official and I dare say, they boys who get visa paydays get virtually nothing from the elite visas, thus the easy rejection if they can push you around a few expensive dodgy visas for a few years first.
volunteer visa lasted many years, there will be a replacement after this one too. Thailands infrastructure is built upon corruption, no one's giving up a payday in any foreseeable future.
