That's because github had the first mover advantage. I remember when most opensource was done on sourceforge or various random svn repos. Github had great UX,

That's because github had the first mover advantage. I remember when most opensource was done on sourceforge or various random svn repos. Github had great UX, had free repos if you were open source, invented the fork + pull request workflow. This made them the de-facto place where opensource was done. Also it pains me how little linus made, even though GitHub made billions from the Msft acquisition.