By reading between the lines of your story and carmack's, my guess is carmack was against facebook user profiling in VR headsets, and you think the sales numbers are sufficient and prove him wrong. If that's the case I'm with Carmack both because "the ideological background" and because the sales argument does not hold : you don't know what the sales would have been (and will be in the future) if facebook did not strong arm users into surrendering their privacy