I've been wondering why open source projects seem to avoid the co-op business structure... imagine if Mozilla regularly distributed some of those google dollars

I've been wondering why open source projects seem to avoid the co-op business structure... imagine if Mozilla regularly distributed some of those google dollars to the entire pool of code contributors. Maybe there are not many serious external source contributions now (though there may well be), but that equation could change in a hurry if there was a meaningful disbursement involved.