Another thing to add to this is that there are different kinds of blockchains. There are proof of work, proof of stake, proof of history and other types. Proof of work is the oldest. It's the slowest and it's the most energy-inefficient. Proof of stake is quick and energy-efficient. Proof of history is even faster; it's like having an atomic clock on the blockchain.
Visa does 65,000 transactions per second; blockchain does 65,000 transactions per second.