"gardening in general" is miles away from commercial growing of cannabis. You don't use expensive grow lights and huge amounts of electricity for gardening in general. You don't need to account for every gram from every plant in gardening in general. You don't need 24 hr. security for gardening in general. Plus they need temperature controlled climate because they want the highest quality and yield. So no, it's not cheap.
Don’t go all bi on me Bob.The mark up on pot is high.