Does a night heater have to be fitted to a vehicle?

When was a kid, about 10 years ago(!) my dad drove tippers for a company called Limmer and Trinidad. This was in the late sixties, early seventies, I even had hair. Anyway, one of the subcontract tipper companies, Walker Bros of Newburn, Newcastle, used to but new Bedford TKs and have the heater radiators removed so the drivers wouldnt run the engines to keep warm!!
Imagine that these days.

hitch:
who in their right mind would wont to sit in the truck when theres a usuable canteen on sight

Well i for one might hitch.

I can read without a TV on a full blast disturbing me. I can catch up on paperwork (no matter how much i might remember to take into the canteen with me, there’ll surely be something else i find i need).
I can make private phone calls in private & without annoying background noise.
I can use the company phone to make work related calls.
I can study the map to see where my next port of call is located.
I can drink my coffee & eat my butties that i’ve brought with me… so i don’t wish to buy food from their canteen on this day… i’ll be buying a meal tonight.
I can have a snooze in a reasonably comfortable position (i never get on the bunk during the day… there’s too much stuff on it).
I can clean the filthy windows & mirrors (different unit every week).

Could probably think of a few more if i tried hard.

Is the above so unreasonable?