The industry is broken. Regulators and Companies conspire to keep the myth of Block Hours alive.
But the company could balance the field if they so wished. Simply base Productivity Pay on duty dime and not block time. If it was set between 110 and 120 hours Duty then many things in the company would naturally even out. It might even be “cost neutral” depending on where they put the line. Predominantly ULR rosters would work a little harder and short haul a little less. Or at least get rewarded when they worked hard. The days off, rest etc would also correct naturally as the company rostered to avoid excessive productivity payment.
My guess is they simply couldn’t care less about fatigue. Until there is an unfortunate event.