Where are the bingo cards... Has there been any Steam threads over the years with no "but.., how about ACTUAL users!" (especially odd argument considering the ratio is basically always linear..) and "but, pc sales, it's dead!" and all other "buts"? ...I hope it never stops though, it's pretty damn funny.
The thing that people don't seem to understand is that there's almost never a way to directly compare the userbase of one service to another. All of the platform owners obfuscate the numbers in different ways. The best you can do is pick a good metric and watch how it changes over time. Concurrent users is as good a metric as any.