[If we are to see both SA and Russia roughly as PPP $25000 per capita economies oil would make $1900 out of these $25k for Russia but at least $13k for the Saudis.
In that sense the difference in the extraction price is meaningless.]
You might have a point in general but it is irrelevant for a discussed issue.
https://m.youtube.com/watch?v=xVXL2Kd5_tM
A requiem to an expensive ruble. They still cry and pay after seven years. Now imagine Saudis devaluing their currency. What else but the oil they have to export?