I totally agree with what you're saying regarding the air brakes. On the other hand, I was driving the bucket (shh, lol) down one of our steep ass hills the other day (31k). I was actually testing out the hydro brakes. I thought it felt pretty competent.. maybe even better than the chip truck, to be honest. Of course I was just trying to get it home safely, so really didn't go so far as to attempt a panic stop or anything too crazy.
Try driving a 68 camaro or 3/4 ton 4x4 with four wheel manual drum brakes and stopping in an emergency. Lol. I can only imagine what the big trucks of that era were like. When men were men.