ELI5 Drones - Why don't we see helicopter sized quadcopters?

Why have remote controlled drones or RC quadcopters become so popular in recent years? If they are a superior design to regular helicopters, why aren't we starting to see full scale quadcopters being built?   ... We explain like i'm five!    Thank you to the r/explainlikeimfive community, and specifically the following reddit users whose questions and responses formed the basis of this conversation: omni314, audigex, cooperred, prionbacon, youngmafia15, gnonthgol & wmccluskey   To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Facebook: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: [email protected]