Happy to answer any follow-up questions here
It's not quite a complete discussion without mentioning the transaction rate/scaling limitations and also Ethereum's sharding approach to this.
On the scalability issue if you sacrifice the decentralization is theoretically possible for Bitcoin to process on-chain, Visa level of transactions and with current energy consumption levels or even less.
You would probably get 3 to 6 physical data center locations probably on the same continent connected with high-speed links with 1 Terabyte 10min blocks.