My thinking is a lot simpler than that. Anything you take off a plant, the plant will replace (ever do a defoliation and wonder why it looks like you didn't a week later?), so I want the plant to replace what's been removed with new growth on top rather than working to grow the lower stuff bigger.On the basis - the lower stuff is just dead mostly or about to be dead and its wet looking, and gonna degrade into mouldy compost whilst still stealing energy from the actual production fans above as it dies slowly, and you get the benefit not just of losing rotting vegetable matter but gain photo energy as its being focussed on better places and improved air flow low down?
That your thinking?
Nick