There are many ways to rank without backlinks. In fact, blacklinking is not even the best way to rank in search engines. The number one way to rank in search engines is good content, which is why blogging can help you rank better than anything else.
A WordPress blog is a great example. Search engines see every blog post as a separate page, which means your 4-page web site would look like a 60-page web site if you wrote one blog post a week. Search engines love text more than they love backlinks.