If it is naive to disbelieve the founders foresaw a future in which automatic weapons and bullets would be so lightweight, cheap and accessible to civilians that anyone could buy them and go on a rampage by themselves that the State could not suppress without dozens of police and SWAT teams you can call me naive.

Gatling Guns came well after the Founding, were large, heavy, hand cranked, cost between $1000 to $1500 to purchase and required a four man crew to operate. They cannot compare to modern weapons.

The Founders were intelligent and capable men but they were not infallible. They knew that too, that’s why Amendments exist.