There was this crazy Twitter thread where some dude extolled the virtues and value of the "10x developer." I thought he was just trolling, but then he doubled down about how serious he was. The larger community called him out pretty hard, but it's still surprising that anyone would think this way. A socially challenged guy (it's always a guy) who codes 12 hours or more a day, every day, praised for "getting shit done," doesn't communicate well, feels entitled because of the volume of work that he does... that's the alpha dev. You don't want him, I assure you.
I saw examples of this pretty early in my career, and I still see it constantly. It's not just young, smart, college drop outs, either. I've seen guys who have operated that way for 30 years and are still employed. The worse flavor of it, dude was two years from retirement. They're terrible to work with, they're the only ones who know about the innards of the software, they believe they're untouchable and they rarely help out the junior folks on the team. They're also pretty much at the center of the toxic bro culture that seems prevalent at a lot of companies, and especially in the valley.
That's not to say that senior developers, true battled-tested folks who have worked in large teams on large scale things, aren't extremely valuable. At a previous job, when I was still writing code, I worked for a company that hired those folks almost exclusively (until they couldn't find any more). That was a dream situation, unsustainable as it was in terms of hiring and cost. But even when the company started spreading out with a better mix of junior and mid-level developers, those good senior devs wrote maintainable, scalable code, and they were generous with their time with the rest of the team.
Is there a multiplier for their output? You might be able to argue that, but what they provide is different. They can lead by example, in code and in process. They know how to work with people from all parts of the business. They're thoughtful about the decisions they make and the long term impact they have. They understand the balance between urgency and importance, and can advocate for the resolution of non-obvious technical challenges. Best of all, if you set them up right, they're going to train their eventual replacements.
But that guy on Twitter and his mythical creature? You don't want one of those.