The short answer is yes, even if it’s by accident.
According to research and analysis, large successful companies that you wouldn’t think need SEO, are using it--without realizing it.
Just look at Nike and Toyota. Both companies spent billions of dollars and decades of marketing resources into positioning themselves as household names.
Even though a keyword strategy wasn’t set up for their websites, the sites are set up to push out updated information on a regular basis. If you look at their strategies, while there may be gaps, they're not being intentional. However, not being intentional doesn't mean they’re not executing strategies that make SEO work.
So, if the “big boys” are doing it and not realizing it, then every business, large and small, needs to be optimizing its website for search engines.
Is there any exceptions? Not really. Maybe, if a business wants a website where they have a web presence only so someone can reference its contact information. Yet, you probably won’t find one business out there with a goal to fail.
If your goal is to succeed, by growing your business and making money, then SEO is one of the more consistent avenues to help you achieve that goal.