I don't quite see it that way. I'm a fan of both characters, and if you've watched or read the original Dragon Ball - you'll see that Goku was very much a unique character to his own right. There was nothing about Goku that was remotely close to Superman. If his character was inspired by anything, he was inspired by the monkey king from the Journey West. The big reveal that Goku is one of the last survivors of an alien race wasn't until Raditz was introduced in Dragon Ball Z. Before then, Goku was just a strange boy with a monkey tail with incredible strength and speed. The way I see it, Toriyama created an original character, and then turned him into Superman...or at least gave him elements of Superman.



Goku definitely shares a lot of similarities with the Man of Steel, but it wasn't always the case. I wouldn't say Superman inspired the creation of Goku, but Superman definitely inspired the idea of Goku being a Saiyan, and him going "Super" Saiyan. It's probably why Western audiences respond more to DBZ than DB... it was originally an adventure story about this little boy who gained friends along the way, and by the time he became an adult, he became a hero who defeated essentially super villains.