Currently school holidays here and we have multiple machines running Steam on Linux all day playing a good variety of games. None of them are competitive online games that require a rootkit so we are just fortunate I guess that the household prefers co-op lan games, sims etc. I suspect these rootkits are about as effective as anti-doping in sports. Determined cheats still cheat so anyone installing malware to play those sorts of games is probably fooling themselves.