Little or no market IMHO. Even today's so called "Work Trucks" have power windows and numerous other creature features.

Exactly.
I needed to replace farm pickup truck in 2014
Would have been content with a decent used one but wanted a full sized box.
Impossible to find anything except extended cabs and short boxes with all the extras.
Heck the salesmen didn't even know what I was looking for and kept showing me more of the same short boxes with 'only x $ a month payments'

Finally found a salesman that would listen to me some distance from home and bought a new truck from him with a towing package about the only extra on it.
Manual windows too but it dose have a radio and AC standard even in basic model.

BTW the new GMC truck I bought in '76 went to scrap in '96