This feels like someone who hasn't been in the industry long enough to know what it is like to try and design software before implementing it with groups larger than 3, and yearns for problems that aren't as complex as the ones they are dealing with. It is easy to build "home cooked" (by his definition) software when you are building for a small number of people by a small number of people. Old Visual Basic programs…
I just don’t sit at home writing more code very often, except to fix bugs I saw at work, or as interviewing prep.
But there was an article here recently that proposed a negative correlation between solo projects and teamwork. And that kind of explains a lot. People who wander off and do large things alone tend to be my more antisocial coworkers. Though I do occasionally see it from socially awkward coworkers who seem to want to be more engaged.
Writing software for other people without talking to them about it is kind of a weird plan.