James was impressive. Galton... did something a bit different; also impressively.

With regard to Galton and psychometrics in general: That's another problem with psychology, that it is a wide field, and somehow (at least in the past) the things that were interesting were difficult to measure, and the things that were easy to measure were not interesting to most people. This is why there were so many different schools in psychology: they often didn't strictly contradict each other, it was more like everyone discussed something else -- and yeah, sometimes they made huge generalization based on the part they studied.

Imagine that you go to a doctor and say: "I feel unhappy, sometimes I have problems to sleep at night, and I don't know why but I noticed myself behaving irationally towards my girlfriend lately. Can you help me, doc?" And the doctor says: "You know, I specialize at something else. I shine people flashlight into their eyes, and measure how many milliseconds it takes them to blink. I have a lot of data, serious statistics and stuff. I can measure how fast you blink, and tell you whether you are a slow-blinker or a fast-blinker with p < 0.0001. Certified 100% pure science."

That's not doing the same thing better; that's doing a different thing. Yes, he is a good scientist, but he didn't answer your question, and he can't cure you. Fifty years later, someone may build a therapy by gradually expanding his research, though.