Of course they also pay nowhere near 20% since they also do a significant amount of sales — often around 30% — via Steam keys sold on third party sites (Humble,

Of course they also pay nowhere near 20% since they also do a significant amount of sales — often around 30% — via Steam keys sold on third party sites (Humble, GMG, Fanatical, etc.) which Valve forgoes all commission on. My guess is most large publishers are paying Valve in the order of 13-15%