I just attended a lecture about this specific comma today. It was there as a rhetorical pause, not to separate clauses. A great example of how ambiguity in punctuation can cause thousands of deaths.
The people designing SQL, not having learned from the mistakes of COBOL, thought that having the syntax as close to English as possible will make it more readable.
I don't maintain any popular projects so I don't have personal experience, but many projects on SourceHut are developed using mailing lists (and outside SourceHut too, notably Linux) and they seem to be organized just fine.
Where is the pricing?