An Oracle database expert, who doesn't understand the necessity of having a primary key? A Java developer who never heard about Map, so he kept implementing it over and over again as a set of methods, for each variable separately?)

Neither of those examples surprise me that much. It’s not that uncommon that being able to produce something that vaguely works well navigating a messed up organization is what it takes to be productive. The bar on not being a totally messed up organization is low but tons of places don’t clear it.