More than half have no code "they own" or OSS contributions they would show off to an interview (the last part is important). That's neither an exaggeration nor trying to find a justification.
They are fathers, amateur musicians, or like to restore old cars. Just to mention a few things. Could they spend 5-10 hours weekly writing code and hacking things together? Yes, but that would be a significant chunk of their spare time, so understandably they do not.
They are fathers, amateur musicians, or like to restore old cars. Just to mention a few things. Could they spend 5-10 hours weekly writing code and hacking things together? Yes, but that would be a significant chunk of their spare time, so understandably they do not.