Any guesses as to whether or not the raw number behind the 15.8% of their Win user base that has 12 GiB or more completely dwarfs the 5555 or so full Bitcoin nodes?
I suspect there are many nodes running on hosted VMs in the sub-12GB RAM range. This category of hosted servers is not even represented in the Steam sample. I actually run a few 3.5GB nodes on Azure and they run real well because of the good connectivity. If you price 12GB VM images on Amazon or Azure you'll find that they run for a couple of hundred dollars a month or more, which is kind of expensive. So I would imagine that hobbyist-run hosted VMs would be the first drop off as RAM requirements went up.