High yield production needs precise control over lighting, needs to have approx 12-12 hour light/dark lighting for blooming, otherwise it'll grow indefinitely unlike most plants which start blossoming at a certain age. Additionally, having good control over irrigation and nutrients with hydroponics can increase yield. And being indoors is good for security against theft, etc.

Freshness has got nothing to do with it, the product has to be dried in a well ventilated area.