> And those limits come up to the theoretical maximum of was it 7 or so and in practice around 4

> https://www.blockchain.com/charts/transactions-per-second

The link you provided indicates transactions added to the mempool per second! The mempool is a cache of broadcast transactions from which miners pick transactions to be added to the next block.

At the current block height, 2700 transactions were in the block. https://mempool.space/block/00000000000000000007a3688746c1d0...

> Also PoW is hilariously inefficient. Because the amount of energy one needs to spend is basically related to the amount of value one could grab by cheating

Your statement is entirely unclear. Could you restate it? For Steelman purposes, I'll ignore the non-sequitur about cheating.

You claim that algorithm x is inefficient in absolute terms? Assuming you're an engineer, you know that engineering operates by comparisons and tradeoffs. PoW is how Bitcoin provides final settlement of transactions and unforgeable costliness compared to existing systems of money (e.g. fiat) and money transfer(e.g. visa, paypal, swift) which are all centralised and built for censorship, while bitcoin is decentralised and censorship resistant. And it provides final settlement of transactions every hour for thousands of transactions. "Finality" and "Unforgeability" are the terms you should attend to. These are both tied to hashrate which is tied to the profitability of mining the heaviest chain.

"Bitcoin has unforgeable costliness, because it costs a lot of electricity to produce new bitcoins. Producing bitcoins cannot be easily faked [..]" [0]

"So what are settlement assurances exactly? They refer to a system’s ability to grant recipients confidence that an inbound transaction will not be reversed. Wire transfers using a messaging system like SWIFT are popular in part because they are practically impossible to reverse. They are considered safe for recipients because originating banks will only release the funds if they are fully present in the sender’s account. [...] recipients of a Bitcoin transaction can have extremely high confidence that, once buried under a few blocks, a transaction is unlikely to be reversed."[1]

> When Satoshi originally devised PoW [...] Energy costs were miniscule.

I'm not sure what you mean. In general, energy costs seem to be dropping over time https://ourworldindata.org/grapher/levelized-cost-of-energy

> [Satoshi] simply didn't foresee the, now obvious, result that it will became a function of burned energy rather than amount of hardware out there.

I'm wary of trying to interpret Satoshi, but here are his own words:

"I think the case will be the same for Bitcoin. The utility of the exchanges made possible by Bitcoin will far exceed the cost of electricity used. Therefore, not having Bitcoin would be the net waste. [...] Each node’s influence on the network is proportional to its CPU power. The only way to show the network how much CPU power you have is to actually use it." [2]

[0]: https://medium.com/@100trillionUSD/modeling-bitcoins-value-w...

[1]: https://medium.com/@nic__carter/its-the-settlement-assurance...

[2]: https://satoshi.nakamotoinstitute.org/posts/bitcointalk/327/