I think it's a relevant and useful measurement from the perspective of, imagine how much better free software would be if the cost spent per user were e.g. 1/2

I think it's a relevant and useful measurement from the perspective of, imagine how much better free software would be if the cost spent per user were e.g. 1/2 (arbitrary) that of the Windows ecosystem cost spent per user. No doubt it's a lot less for free software, and that's fine. But that cost should be higher via companies and governments in particular, contributing more dollars voluntary, with donations and development for free software. Not merely free no cost, but libre free, as in repurposable.