Good point AA-- but you left out another big issue-- that being rest and recovery!!
If you do that many sets, which i wouldnt recommend, and your nutrition is based around your insane workout, and you sleep 12-14 hrs. I dont see why anyone couldnt do 30,40,50,90 set workouts?????? but then again -- I do have another life outside bodybuilding. Holla if ya heeeer me!!!!!!!!!!