Last time I checked; airline application criteria, JAR OPs requirements, etc. the qualification for pilots did not include insomniac.
There is a big difference between the 'macho right stuff' and today's professional airline pilot. Passengers expect top quality sharp alert pilots.
Been there, done that, got the t-shirt and the red eye, and the bad back, and the indigestion, and the near divorce and...........
If any pax complains about crews pulling off flights for tiredness, I'd always ask if they'd feel happy about being in the hands of a pilot who had slept only 4 hours in the previous 24, had 6 hours jet lag, and would be landing them 20 lours later on an NPA or circle, in lousy weather conditions. Hands up those who want to stay on board and go now, or wait 10 hours for the crew to get some sleep.
Remember, the decision about fatigue is difficult. If you start the duty tired, there is a good chance it'll be worse at the end, likely fatigued. Most companies will ask if you're refusing the flight due to fatigue now. That is not the case. It is your assessment of what you will be in 16 hours +. Even if you are fresh now, then in 16+ you will be tired. If you are tired now, in 16+ your will zombied.
And no cadet pilot went to flying school signing up for this manure. It's the 21st century, for heavens sake. Let 411A and his cronies live in the past, like the L1011.