... how are the geniuses expected to differentiate themselves from the crackpots? ...
That's what open source and peer review are all about. The code speaks for the coder (sometimes the coder gets to speak for him/herself too, when asked), and the community sorts out the competent from the incompetent.
Of course even in this arena, whether a good piece of open source code really gets the usage and notariety it deserves may still be a hit-or-miss, luck-of-the-draw kind of process. (And it's possible that some really poor code gets into the "standard tool set" for a while, but sooner or later, it will get phased out.)
