I have a '65 one ton. As has been said, they aren't as desirable as a shortbed 1/2 ton, and were less common to start with, so not many around anymore. If I hadn't have bought mine it would almost certainly have been scrapped. On the other hand, they are cheap dependable work trucks if you have basic mechanical skills. I still see several 1960-1972 3/4's and one tons around working, and a few "big bolts". Never really see any old straight axle trucks around here besides hot rods and the like. My guess is that most were scrapped when the front axle wore out.
Some of my crap:
1963 C-30 flatbed dually 292/SM420
1965 C-10 LWB fleet 250/column shift 3 speed
1965 C-30 9' stepside 250/SM420/4.10 gears (my DD)
Website I made for my crap:
http://www.66submarine.com