Discs started to appear on large trucks 20 years ago,air operated.Too many problems and really offered no better stopping ability, so they lost interest.But you will find disc fronts on many trucks in the 10,000 lbs gross weight range.
I used to road race motorcycles on drum brakes back when, halfway through the brakes were useless, faded away.The first discs were better, but not by much,but in time they improved.
You could order a big block Camaro or Chevelle with the tiny 9.5 drums,not the best.
Disc brakes also offer greater control over wheel lock up than drums, especially the Bendix self servo drums .
