Making something useful starts with a vision. It starts with a person or team having an idea of a better way the world can work who then bend the world to fit that vision. I imagine this is how Apple’s new 3D Touch came to life – one of its creators tweeted that the process of creating it took 5 years. 5 years of pushing the technology where it needed to be to create their vision.
Less often, a person or team see the way something behaves today or accidentally stumble upon the right combination of factors to create something useful. I’m thinking about discoveries like penicillin.
Both ways work, but only one is reliable. You could spend lifetimes waiting for your penicillin idea and come up with nothing. Training yourself in the skills to have a vision and bend the world to it will always get you something.