- working for a company which doesn't allow external contributions
- working on stuff which doesn't make sense on GitHub (does anyone care about a servo driver for a specific component used only on this board?)
- working for orgs where they're not allowed to say much beyond "I'm working for the government"
- not being interested in opensource (gasp!)
- word of mouth, specific industry consulting
Creating a LinkedIn account takes what, 30 minutes? You don't need to be one of those high achieving "Can you endorse me for X/Y/Z on LinkedIn" morons to "be on LinkedIn".
Similarly, your parent didn't for a Github account with weekly contributions to OSS projects. Let's be honest, I've seen so many accounts that are just "I was bored during a long weekend and threw together this 200 line utility script". And that's great!
This reduction of people into black and white comes up again and again in this discussion, and I cannot understand it to this day.
> if someone was not on LinkedIn or didn’t have a public Git account, I found myself thinking ‘well, what exactly do they do?’
How about spending time with their family, Hanging out with friends. Relaxing and refreshing themselves so they are fresh and ready to go in the morning.