I can't answer for the File Pilot author but I've spent many years on writing a file manager.
* It's fun to write and to use. It's like craftmanship.
* Hopefully some companies/people will realize how many hours they waste using the default OS file manager
* It's less risky than developing a game full time (I think)
* Sure, I lost a lot of money to not having a normal job but my bills are low and my priority is more happiness
I've come to realize (mainly by reading comments on this very forum) that, for an increasing amount of people, programming is just a job and they don't see it as an art form or a hobby. They genuinely cannot fathom that someone would spend time on ANY project without being paid.
It's very sad but ultimately society couldn't function of we only hired passion-driven programmers, so eh.
