There are far more devices running Linux in the world than Windows & macOS combined. That would seem to be a much more useful comparison than how many people own those devices.
Parent post was updated to say "not counting servers and embedded", but dismissing smartphones -- literally the most popular type of personal computing device in the world -- this way seems to completely invalidate the point.
The parent thread was about possible backdoors; more devices running a piece of software = more surface area for any possible backdoor in that software.
Parent post was updated to say "not counting servers and embedded", but dismissing smartphones -- literally the most popular type of personal computing device in the world -- this way seems to completely invalidate the point.