This is a typical example of survivor bias. You are overly emphasizing successful people's view as generalized truth. The fact is, these are the same leaders wh

This is a typical example of survivor bias. You are overly emphasizing successful people's view as generalized truth. The fact is, these are the same leaders who also missed out boat on entire social revolution. They are not often not right but it hurts them lot less because they have already amassed huge momentum. For hackers, makers, creators, hobbyists - I don't think you should put any artificial restrictions on what you should work on. If you think it's the most interesting thing you could be doing right now, may be its useful to you and may-may-be to your friends - go do it. Don't think about if it has good monetization or if it would be used X times a day or it would put you in the TechCrunch etc.