> zero experience in building a major service that custodies billions in other peoples' money.
This is exactly what the Dunning-Kruger effect describes. He was incompetent at the task he was doing and didn't know enough to be aware of his incompetence.
What you might be thinking of is the smbc Mt. Stupid diagram [1] which does relate overinflated sense of know-how to a relatively low experience level.
That is distinct from the DK effect in important ways. Of course it doesn't help that if you google images for DK effect 19/20 first results will be a bastardisation of the Mt Stupid comic.
This is a common misconception. Wikipedia has a pretty good write-up. Quoting the first paragraph:
> The Dunning–Kruger effect is a cognitive bias in which people with limited competence in a particular domain overestimate their abilities. Some researchers also include the opposite effect for high performers: their tendency to underestimate their skills. In popular culture, the Dunning–Kruger effect is often misunderstood as a claim about general overconfidence of people with low intelligence instead of specific overconfidence of people unskilled at a particular task.
The original paper [1] was explicit that this was domain-dependent.
> The point of the DK effect was even with experience, the disparity between ones competence and awareness of ones relative competence doesn't improve.
I don't think this is consistent with the literature. In the studies I'm familiar with, there is the classic Socrates effect that the people with the most skill are aware of how little they know and tend to underestimate their relative performance. So it improves significantly, but there's a slight over-correction.
Quoting the original paper:
> improving the skills of participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities.
[0] https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect