If you think about the majority of the population owning a smart phone, or sitting at a computer for their job, at some point during the day, most people are making some type of search on the internet. Search engines are great, because they provide targeted traffic to your website. It makes growing a business easier, because the people visiting your site are actually looking for what you can offer them. The only way for search engines to get traffic to your website, is if the search engine itself, can find it. As targeted traffic comes to your website, you are going to gain exposure, publicity, and revenue which show that SEO is absolutely necessary.
Finding someone that can optimize your website for search engines does come with costs. Some people think that they can just do SEO themselves, and they are correct. The basics of SEO can be accomplished on your own, if you are willing to put in the time and study. Hiring someone who has optimized many sites and knows what Google and other search engines are looking for can achieve your results much faster.
It comes down to asking yourself just how much your time is worth. To cover the expense of hiring a knowledgeable SEO agent to build your ranks, how many hours would you need to work to cover that? Now that you have your numbers, is it justifiable to spend that time studying and testing different techniques until you find something that might rank a keyword on your website?