I think everyone here can agree with the following:
Quality Content + Traffic = Conversions
Traffic can be attained thousands of different ways.
Do you specifically need search engine traffic to have a successful website? NO!
You DO, however, need quality content! If your visitors don't like what they see (what you have to offer), they aren't going to take any action based on what you've shown them!
While traffic plays a role in the sheer number of conversions you attract, content is what fuels your bottom line. Without quality content your website will NOT be profitable.
CONTENT IS KING!