When you think about it, everything around you started from a design.
Your desk. Your shoes. Your phone. Your computer. Your bed. Even that random paper clip you play with for hours when you start running out of ideas. This is how important designers are.
Building a responsive web site from scratch is all well and good, but it's another matter to take an existing site and give it a responsive web design refit when there's likely to be a mountain of legacy assets and content to take into consideration.