Eventually it will become cheaper to employ a few more pilots rather than pay pilots to sit at home on the sick with fatigue...........as always money will be the driving force.
But if your pilots are "self-employed" you don't pay them when they are off sick, so you don't care.
On a slightly different theme, when Australian train drivers wore found to be falling asleep when their train was crossing the many miles of the flat, featureless Nullabor Plain, the solution was to introduce the "Dead Man's Handle". The deadman has two states, say UP and DOWN. It does not any direct effect on the train when operating normally, but if its state is not changed from UP to DOWN, or vice versa, every few seconds, the drive is disengaged and the brakes applied.
You cannot apply the brakes on an aircraft in flight, but it should be easy to set up the system to make a loud noise if neither the flight controls nor the deadman are moved within a specified time.