I'm relatively new to the workforce so take this with a grain of salt, but I think this is a false dichotomy. People who are less agreeable, more assertive will make more money because they negotiate more on their own behalf. The poster child for these people, especially from the dev's point of view, is that of a brogrammer/scumbag/dick stereotype, and by definition they make more noise than the kind and also competent engineer.

You could also say that humankind is still stuck in an evolutionary stage where in most places, being dominant is the best signal of "value". In a Tim Ferriss podcast, Ray Dalio actually mentions that disagreements at Bridgewater can take on different forms, because some people are less suitable for verbal, thinking-on-their-feet sort of debates, and might be better suited for long form (like Hacker News threads) debates.