This only works in big or medium companies, fortunately being over-confident without actually delivering stuff gets caught pretty soon in small companies (because it directly and adversely influences the bottom-line). In other words, small-company bosses/owners don’t really care of how confident you are, they only care about actual work that makes the clients happy, so that the bills and the salaries can be paid at the end of the month. That’s one of the main reasons why I’ve worked only for small software shops in my career, I can’t stand the wannabe people who always brag about themselves without actually doing anything of value.

This works also great in startups where nobody really knows what he is doing and no one has firm grasp on what people produce/should produce except impressions. Knowing who really produces requires good management that has time to look at the details. That requires stability, non panic mode and sane politics.

Overworked manager will take overconfident person over humble cautious one, because the illusion feels good.

Those overconfident people rarely do nothing and are completely incapable. That is strawman situation, basically. Oftentimes they eventually succeed, altrough it takes more time, is overall somewhat less effective, their code is harder to maintain or something of that sort.

Marissa Mayer - https://en.wikipedia.org/wiki/Marissa_Mayer

By all accounts she seemed to be a great product manager, but product management isn't organizational leadership.

Likewise there is Hugh Jones - https://www.sabre.com/insights/releases/hugh-jones-to-head-t...

Hugh Jones was known for tenacious leadership in large volume business operations, but experience in retail and product was limited or absent.