Hardly.
There is a great amount of value in SEO, but online success cannot rely on SEO alone. SEO focuses on getting your on-page elements just right so your site can be recognized for the value it has. But SEO doesn’t create the value.
Website value, and therefore what truly earns those top rankings you want, is done with good on and off-page marketing messages and promotion. Think of it this way, SEO merely clears the debris out of the way so the search engines can review your site. But what they see in that review is dependent on so many other things.
So next time you start thinking you just need more SEO, make sure you’re not neglecting other smart online marketing strategies. Good SEO requires more than SEO to survive.