"at scale" assumes a popular game - and you end up by giving as an example one of the most popular FPSes ever ! Please give an example of a game with, say, less than a million of copies sold / given away ? (And ideally, not an FPS, we all know these have specific extra challenges involved.)

And "at scale" pretty much means that matches are not competitive, because the sums required for entering a tournament game and given for winning it are going to be too small, won't they ?

P.S.: And for non-competitive games, I would expect that this cheating issue (among others) would be aggravated if you insist on playing with total strangers you will never see again (also part of the scale issue) - maybe just avoid that ?