Actually, not as far off as today's experts would have you believe, particularly with the cars back then and typical speeds about 60 mph. At 60 mph or 88 feet per second, two seconds is 176 feet. That divided by 6 (for 60 mph) would be 29 feet. So six car lengths wasn't even enough at 60. For today's sized cars you need more like 8 or 9 car lengths at 60 mph to have 2 second following distance.
Yee gads! They taught me to tailgate in driver's ed in 1959.
BTW, who among us are able to gauge the distance to the vehicle we are following in "car lengths?" A dumb impracticable idea which was widely taught - to absolutely no benefit. Not sure if driver education now uses the "seconds" rule. I only learned it after I started riding a motorcycle, but it is very useable: "one thousand one, one thousand two, one thousand three," and I use it often with both bike and car. I agree that two seconds is the minimum and three seconds better.
I'm pretty sure this novel idea has not entered the craniums of most motorists. Recall a trip in very light traffic on the Coquihalla, where the posted speed is 110 kph and most people on this summer day are doing around 125. I'm in the right lane doing about 120 when I see a train of 7-8 cars slowly passing me, the separation between cars only about a car length. TROUBLE! I slow down to let them pass me, and then presumably pass the driver that is holding the even faster drivers up. Doesn't happen. That train just continues down the fast lane, with huge gaps both ahead of and behind them. Couldn't help thinking "what if a deer jumps out in front of the first car." You could have a seven-car collision with multiple fatalities. It didn't happen that day. But what a stupid gamble for no reason.
Sorry if I have sidetracked this thread. Never commuted to work on the bike and in my travels on the bike never had encounters/near misses with anything on the road - except another rider who totaled my bike. That is a story already told in "crash chronicles."