Very very few of these people exist. They like to think that because they are very good at writing and understanding code and technology that they are automatically the smartest person in the room with every other aspect of the business. And I'm not talking exclusively about software developers, you'll find the same issues with anyone who is deeply smart and experienced at any one thing, thinking they must be smart about everything else too.
There are a few polymaths out there, yes. But only a few.
Well, yeah, that's why they're considered good. Why they get a special title not given to everyone else. It would be nonsensical for "good dev" to refer to everyone who touches software development. "dev" would already communicate everything you need to know. The addition of “good” implies being set apart from what is typical.
There are a few polymaths out there, yes. But only a few.