Hi Emma! I agree that something like engineering or software development could also answer that question, but design is unique in that it's not as bound by methodology/ theory as software development may be. Whereas CS is largely a left brain logic-based process, design is generative and relies on abductive thinking, which encourages new and innovative ways of doing things. This distinguishes design from other fields, and is something everyone should be able to do, not just designers!
It takes a whole lot of collaborators to bring a solution to life - design functions best with and/or within software development, engineering, business, etc., and definitely not alone. Thanks a lot for your feedback!