None of those things describe a good programmer
Honestly, it sounds like John was a problem and needed to be fired a long time ago, before he created this unmaintainable mess.
Every single other person could also be called the problem, because they knowingly let John do all the work, and apparently weren’t interested in sharing the responsibility.
If someone else is getting paid the most amount of money, I’m happy to let the most amount of work fall to them. “Sharing the responsibility” doesn’t make sense if I don’t get to share the reward. It’s a company, not a community or a family.
“Failure of leadership”
Yeah. Always cross train, always document. What if John had died?
What if John had died?
Ah yes, the car/train/plane crash argument.
Bus factor.