agreed, good point. ultimately a single unit will be capped by the outlet power limit (~1500W in US i think). People can just buy multiples and stack them together each with a separate power supply but physical space will limit such setup. I am hopeful there will be many data centers spread out around the world to host those machines once the asic caps out, as oppose to a few large data centers which will pose a significant risk to bitcoin, as it is nothing without the backing of its network.