Another aspect is that in a lot of disciplines, a certain level of maniacal persistence increases your chance of success. To take the "mythical" 10k hours to mastery, it's a lot easier to get to 10k hours if you're not spending time getting in 10k hours of socialisation.

I say this as someone who myself would much rather code than spend time socialising most days - it's certainly not meant to imply that everyone introvert or who spends most of their time coding are assholes (that'd implicate myself...), but that there's a level of correlation between being good and spending lots of time practising and not spending as much time thinking about social niceties, and not everyone manages to strike the right balance.