Well at the time I thought it was a good idea and believe if something similar were to be adopted today, then there would be fewer complaints about people sitting with their foot on the brake pedal and dazzling the occupants of the car behind at night.
The brake lights need to be bright enough to be seen in bright sunlight. But there’s no reason for them to be that bright at night, as long as there’s still a clear difference between taillights and brake lights. So I think it’s a good idea, but it’ll never catch on because people - and car manufacturers - seem to think it’s better to have lights as bright as possible.
And when braking from high speed in fog, no-one will see the dimmed brake lights.
Recipe for multiple pileups
High speed in fog ... really? You would of course have the rear foglights on in fog, which are brighter than brake lights and really do encourage you to keep a safe distance.