This way doesn't secure the future of the software and does not promote longevity. You get what you pay for. If you want free alternatives may i suggest PHPbb or sMf?I think if a software comes out new, should be free. Once its gets bigger it should then switch to paid like most software. Also if you had the software when it was free you should be able to upgrade for free.
This is what I said about that: http://xenforo.com/community/threads/suggestion-free-developer-licences.912/page-3#post-11902
The first versions should be a test version, to give people a reason to buy it.This is what I said about that: http://xenforo.com/community/thread...12/page-3#post-11902