The situation I've encountered is a jerk who was actually fairly mediocre in his abilities but whose bully characteristics and brash confidence had led many of the non-technical people in the company to believe he was extremely skilled. I think one reason people become bullies is because they know they can't back up their decisions with skill. Linus is brash, but is quite able to work well with people and has the res…
1) The whole 10x thing. The implication being that if you're brilliant, you're worth an entire team or more; if you're average, you're... worthless. Thus, you have to be better than everyone else to be worth anything
2) Classic bro culture - somebody who gets rewarded for being obnoxious, bullying, and "alpha" is a very "bro" thing.
3) Tech people tend to be people who put a lot of their self esteem in their intellectual - and work - abilities. This means they get more defensive when that ability is threatened.
It's a culture that rewards being brash and confident. Can you imagine someone saying that they are an average programmer but work well with a team to get done a lot?
There are definitely people who quietly get a lot of work done, and there are people who are "force multipliers" who make the rest of the team more productive (something I regularly try to do, incidentally). Depending on the culture these things can get ignored pretty easily - the 10x developer is an individual with limitless skill in the classic view.
There's not really a space for an "average" developer - everybody has to be a "Rock star" or "10x" developer. We only hire the top 1%, etc. So if you aren't, what else can you do but fake it?