That's really not how people work. Haven't you ever programmed all day at work and then gone home to work on a personal project? It's very easy to get a second wind when changing projects, especially if it is something you find enjoyable.
And for all we know this was something that someone built outside of work they realized could be put to this use.
And for all we know this was something that someone built outside of work they realized could be put to this use.