The cost estimate was based on what what you and I would have to pay if we were to train AlphaGo Zero in 40 days on the given hardware using the reported number

The cost estimate was based on what what you and I would have to pay if we were to train AlphaGo Zero in 40 days on the given hardware using the reported number of games and resources. Just replace the self-play TPU resources with commodity hardware or even just cheaper GPU compute providers and you'd reduce cost 10-fold by just not using TPUs. Same goes for the number of self-play games. That still doesn't change the estimate itself. IF the other projects would've used Google TPUs, they'd well have been around the same cost as the estimate. I really don't understand what you're trying to argue against here.