Whether the average developer uses a debugger or not is much more correlated with the tools at hand than anything else.
People who unit test or don't is more correlated with age and commercial experience / maturity level. Although those correlation curves aren't monotonic either.
I spend a lot of my time helping people get unstuck and I notice patterns.
People who don’t use the tools seem to trust their own eyeballs more than they trust code. Even as someone who spots bits of code that nobody else sees, I don’t trust my eyes that much. It’s not a matter of if I can spot things, because I can, but it’s not a reliable skill.
It’s a matter of reliability and a matter of saving that energy for the next step.
People who unit test or don't is more correlated with age and commercial experience / maturity level. Although those correlation curves aren't monotonic either.