I think one obvious point is that the minds dedicated to increasing ad clickthrough generate the revenue needed for other great minds to embark on projects like

I think one obvious point is that the minds dedicated to increasing ad clickthrough generate the revenue needed for other great minds to embark on projects like self-driving cars, glass, and, you know, only indexing the entire internet. Also, not everyone on the planet is interested in becoming a doctor. People have different interests. The ones who are not people who want to solve those problems, instead support the economy that allows people who are doctors to do their work and make scientific advances. To simplify, if we were all capable of working on these things, and we all did so, it wouldn't be any better because we'd all die from lack of food, because none of us are doing menial things like being farmers and cashiers.