That "gold standard SWR device" looks like a big resister with screw terminals hidden inside of a big heat sink.
There was some company, in the neighborhood of 20 years ago, who was marketing a magic antenna with a secret box that you hooked the wires to. Someone (was this in QST or 73?) who finally reviewed it took the secret box apart, cleaned out all thegunkheat sink material around the central component, and discovered... a big 50 ohm resistor bank. So of course the antenna always presented a 1:1 SWR, all the radio saw was the resistors.
After the review was published, if memory serves, the magic antenna and the company marketing it quickly disappeared.