As if ..... Where's he going? That many feet changes nothing. I live in a city famous for leaving a lot of space between cars, there are memes about it. So for this thread I'll explain a couple of why's:

1. Me personally , it became a habit when car jackings became a possibility. A less easy target mentality.
2. Insurance is crazy high here and so ,as you mentioned, the not being forced into the car ahead of you .
3. There have been multiple shootings in road rage in this city over the last year. Everyone kinda wants space and eyes on others or what may be happening, room to react or move. Also not into riding a cars bumper and maybe causing another incident.

I'm sure there are as many reasons as there are people, but these are the obvious ones.