can't the search engines figure out my site without SEO help?

Why
Search engines are always working towards improving their technology to crawl the web more deeply and return increasingly relevant results to users. However, there is and will always be a limit to how search engines can operate. Whereas, the right moves can net you thousands of visitors and attention, the wrong moves can hide or bury your site deep in the search results where visibility is minimal. In addition to making content available to search engines, SEO can also help boost rankings so that content that has been found will be placed where searchers will more readily see it. The online environment is becoming increasingly competitive, and those companies who perform SEO will have a decided advantage in visitors and customers.