Give me a break. The older generation "dreamed of greatness" and now no young people do anymore? Isn't this the same thing that every generation says about the previous generation?
The tools and technologies that are already changing the world today, and that will change the world tomorrow, are being worked on by people who might fit the description of San Francisco hipsters. Who do you think works on Twitter? Facebook? Who do you think works on the iPhone? These are products that are already having an impact on society, and it's not just the old guys who are working on them. And as for the "current" generation, what about companies like Square, Heroku, and SimpleGeo? Is that what you call mediocrity? Get off of your high horse.