But as a percentage of the installed base of platforms, it's losing that position at a rapid rate.
That's what various advocates would have you believe. Mostly, what those are based on are a 1 or 2% slide over the last three years - you're supposed to assume that trend will last forever and extrapolate accordingly. The same sort of calculations that global warming wackos use to "predict" average daily temperatures of 240 degrees fifty years from now, IOW.