Regarding the open source frontend, what's that have to do with profitability? We think that, if anything, having an open source frontend will lower costs because our users can help us build the features they want.
Regarding assurance, I believe the expression goes: "The only two things certain in life are death and taxes" (Benjamin Franklin?). That said, we're a real company with employees located in San Francisco and we're planning on being around for a long time.
And to answer your question, no, we're not profitable at $8/credit, so you should definitely stock up because this special won't last for long.