I suspect John Carmack is aware of the tradeoffs and has better things to do with his time than procure $50k+ worth of compute resources, rack and stack them in

I suspect John Carmack is aware of the tradeoffs and has better things to do with his time than procure $50k+ worth of compute resources, rack and stack them in his bedroom, provision them, implement configuration management, orchestration, and monitoring, keep them running over time, etc., etc., etc.