people who say that this is something they do/would want
Why aren't these people using the sites that already exist? You could just say "that's because the questions/answers aren't good enough," but my guess is most of these people who say they would want it never got as far as looking at these other sites in order to see their quality of questions and answers.
They do, but they aren't satisfied. I've had a lot of people say "I wish this existed when I was applying to college", implying that they want something beyond what they already had. A lot of these people are people that I know looked through the questions (because a lot of them answered them, and because a lot of them were in the context of conversations where we either looked at the site, or I explained and gave examples of the questions).
My motivation behind this post stems from Aumann's agreement theorem. It seems that my opinions on startups differ from most of the rationality community, so I want to share my thoughts, and hear your thoughts, so we could reach a better conclusion.
I think that if you're smart and hard working, there's a pretty good chance that you achieve financial independence within a decade of the beginning of your journey to start a startup. And that's my conservative estimate.
"Achieve financial independence" only scratches the surface of the benefits of succeeding with a startup. If you're an altruist, you'll get to help a lot of other people too. And making millions of dollars will also allow you the leverage you need to make riskier investments with much higher expected values, allowing you to grow your money quickly so you could do more good.
A lot of this is predicated on my belief that you have a good chance at succeeding if you're smart and hardworking, so let me explain why I think this.
Along the lines of reductionism, "success with a startup" is an outcome (I guess we could define success as a $5-10M exit in under 10 years). And outcomes consist of their components. My argument consists of breaking the main outcome into it's components, and then arguing that the components are all likely enough for the main outcome to be likely.
I think that the 4 components are:
The Idea
Your idea has to be for a product or service (I'll just say product to keep things simple) that creates demand, and can be met profitably. In other words, make something people want (this article spells it out pretty well).
What could go wrong?