Edit: Let me offer a different way to look at it.
Does having a well organized website help turn visitors into clients? Yes. Well that's SEO, a well organized website.
Does having useful and well written information about the services and products you offer, or you industry, help your business? Yes. Well that's SEO too.
Can sharing your knowledge online across different relevant forums help you grow your brand and business? Yes. Well that's SEO as well.
It is just that people who do not know SEO think it is things such as keywords and metatags and url structure, but everything above and more is SEO. And all these things work to your advantage, therefore SEO works.