Concept cars look beautiful and futuristic, but why do manufacturers spend millions developing them if they're never going to make it into production? Take, for example, the DS X e-tense, a "2035 dream car" produced by the French luxury brand DS. Half open-topped sports car, half luxury saloon, its outlandish styling looks as though it has come straight from the pages of a superhero magazine. It is designed to show what the company thinks a hugely powerful, all-electric self-driving machine might actually be like. It bears little relation to anything the brand currently produces, but that is hardly the point.