> it takes less than one second to go through
Like Bitcoin used to be before someone had the brilliant idea of destroy the possibility of zero-confirmation transactions on-chain with Replace-by-fee transactions
> Except people wanting to do more than 15 transactions a minute
It's more like 7 transactions per second, which is still absolute crap, but that was after the original Bitcoin project was kidnapped. There aren't such limitations in the original Bitcoin (forked as Bitcoin Cash)
> Or that to scale everyone would need to store a petabyte size blockchain
That is addressed in the whitepaper (SPVs and pruning)