... you just don't see them out in the winter. Why? they suck in the snow and I wouldn't want to do a panic stop with any type of trailer with the original brakes or steering. ...
have to disagree goneagain, they can
do just fine in snow 
in addition, the truck in question here was about a panel, which does even better than a pickup because they have better weight distribution, and there's no reason electric wipers can't be fitted to any year - I've been using pre-72 trucks as daily drivers for decades, local and cross country
Bill