Back in "the day" you could have a toilet that lazily filled up and you only really needed a mild flow rate to send everything for a ride because once that 5gal of water starts spinning it's taking everything with it no questions asked.
You need a big hole to dump the tank fast to get the maximum kick out of that federally regulated amount of water you're allowed to dump per flush.
Plumbing fixture and residential water consumption regulation in the US is a textbook example of "should be a states issue". The feds basically let the desert states dictate everything and then everywhere east of approx the Missouri river has to suffer through washers that don't wash clothes the first time, constantly clogging drain traps, sewer lines, municipal mains, reduced septic performance, etc, etc. None of this is necessary in the nearly universally surface water consuming east. They'd all be better off using more water and having to size their water treatment plants up a notch to handle it.
You need a big hole to dump the tank fast to get the maximum kick out of that federally regulated amount of water you're allowed to dump per flush.
Plumbing fixture and residential water consumption regulation in the US is a textbook example of "should be a states issue". The feds basically let the desert states dictate everything and then everywhere east of approx the Missouri river has to suffer through washers that don't wash clothes the first time, constantly clogging drain traps, sewer lines, municipal mains, reduced septic performance, etc, etc. None of this is necessary in the nearly universally surface water consuming east. They'd all be better off using more water and having to size their water treatment plants up a notch to handle it.