I wonder how much of this is context-specific.
It makes sense that if you grow outside defoliation is likely counter-productive, I think where it gets greyer is when you move inside and how big or small your space is. In my little grow space, I need to defoliate(photoperiod) just to keep the air moving. So I get a yeild increase just because I don't loose plants to PM.
I wonder too if lighting would affect that too, if you have lights that give you a deeper PPFD sweet zone or do you have jsut enough to get the job done?