[vkou]

If we care about reducing following distance, we should be lowering speed limits. A car doing 60 needs a much longer safer braking distance than one doing 45.

Also, if you are following at a distance where an AEB activation will cause you to rearend the vehicle in front of you, you are too close to safely follow any vehicle, regardless of whether it has an AEB.

[HPsquared]

Depending on where you live, if you leave a big gap someone else will just fill that space and you're back to the "short following distance" mode again. Rinse and repeat...

[vkou]

And then when the car in front has to tap the brakes for whatever reason, the tailgater has to slam them to avoid a collision, the person tailgating them also slams theirs, and you get a wave of braking propagating backwards, eventually creating a traffic jam.