Why doesn't Big Sur Terminal set environmental variables?

I found that COLUMNS is no longer set, and it caused issues using vi edit mode in the shell.

I found nothing in Apple's docs about environmental variables, but did find this online:

https:// + ss64.com + /osx/syntax-env_vars.html

which lists a slew of variables, most of which I don't see.

I don't see any option in Preferences to enable or disable this.

HELP!
Why doesn't Big Sur Terminal set environmental variables?
 
 
Q