Of course, the real problem is that there are certain spaces that wouldn't really be serviced if that's all we did. Education is an excellent example: the people who really feel the pains of education, students, won't really start having the ability to help solve those pains until they're further along in their education, at which point the earlier pains don't necessarily apply as well. In a similar vein, learning to program is a problem that's been on the map for a long time, and, while the situation is constantly improving, we're dealing with the problem of, by the time we've got the skills to really help solve it, we've already learned to program, and have lost some amount of sight of how learning could be improved, because we're no longer in the proverbial trenches.
So while “scratch a personal itch” is awesome advice, and almost certainly helps in product development and framework development, sometimes it isn't enough. Sometimes just following your curiosity or intuition and exploring a space that doesn't produce regular hurt for you can lead to an equally good result. At that point, what you need to make sure you have is external feedback from the people whose itch you're trying to scratch. Maybe the chances of failure are greater in these cases, but the opportunities for success are also probably greater.