While vision is important I do agree with the article how sometimes you discover the vision by doing small things. Facebook I don't believe was any more visionary when they first started. It first started as a knockoff of hotornot (if memory serves me correct). But by doing that project he realized and got on to the path that would lead to Facebook.
As much as I would like to wake up one day with THE billion dollar idea... I don't think that's how it happens. I think for most people it's about doing things and adjusting as you get more data to figure out what direction to go. But if you don't start and worry instead about chasing after the huge problem to solve...you might just end up waiting too long and passing on opportunities.