Some of the tools we use everyday were created by people after they made their first billion dollars. iPhone and Microsoft Office, for example.

People will always create things, but if you have more money than you know what to do with, and your mind is not worried about working to put a roof over your head, then your mind is free to imagine and build the next world-changing thing.

Capping the income would then also put a cap on innovation. This is not necessarily bad; many people think we could have enjoyed a few more decades before the creation of the smartphone.