Linux is a free open source system; therefore, web hosting service providers do not need to pay licensing fees for using Linux as their hosting servers' operating system. Therefore, web hosting providers are able to offer lower prices for this type of web hosting service.
Since the common SEO practices relate to website coding (e.g. meta description tag, title tags, H1 tags, H2 tags, etc.), one may ask: "what does hosting have to do with SEO?" In fact, Google recently has announced that Page Speed is a factor in its search ranking algorithms. So the faster your website loads, the better it ranks on Google. With that being said, it makes sense for a website owner to choose a more reliable web hosting service provider for SEO purposes.