Copyright law is also how poor people avoid being exploited by mega-corporations.
It's not easy for an individual artist or self-published writer to sue Disney - but copyright law is what prevents Disney, Paramount, Warner Bros. etc. from just mass-grabbing stories and art and turning them into movies for their own profit. The fact that the law exists keeps them from grabbing everything they can.
There are occasional cases of "we're pretty sure this was grabbed from someone else's idea," but Sega couldn't grab Flappy Bird and distribute it through their channels because of copyright.
Copyright law has problems and needs a major overhaul but it is better than no protection at all.