Assigning individual blame is missing the point of improving the security culture in general
Scenario 1: 20% of staff tested failed. Individual targeting is pointless because the issue is systemic. This has happened in aviation, it’s common for accident investigators to conclude that the entire company culture (or even the entire industry) has failed to handle a problem. They don’t waste time in cases like this pointing at individuals.
Scenario 2: you test very regularly and nobody fails the tests. Except Bob, he fails the tests. In this scenario, your threat analysis document will recommend retraining, firing, or restricting Bob specifically.
Scenario 2 almost never happens because nobody has data that good. If your sampling frequency or ability to conduct tests are limited, no specific sample is enough to cover the entire problem. If you focus on a punishing (or just re-educating) the 20% who failed then your next test will fail for (potentially) 20% of the 80% who weren’t retrained, and thus didn’t learn anything.
TLDR: you need to choose the approach based on the situation, but we collectively tend to treat security poorly enough that we’re almost never in the fortunate situation where scenario 2 fits.
Yes in general, because usually it's culture and not an individual failing. No in specific situations, because it's not just culture but also some people are just the weakest link.
Only focusing on either of these while ignoring the other is going to lead to bad results.