Well, technically, the "Economics 101" thing that you were looking for is more along the lines of "more supply with the same level of demand = lower price" (or same supply with less demand, which probably doesn't apply here
). Although it might amount to the same thing if it is true that "since the consumers aren't deterred by the current cannabis laws, demand will not change much." Then again, there are plenty of people in the "but those consumers will consume a whole lot more of it" camp... So, it could either go down, stay the same, or even conceivably (but almost certainly not bloody likely) go up depending on whether the supply significantly increases in proportion to the demand.
It costs to grow quality but "very expensive" is highly debatable. Compared to current prices, not so much. When even the most expensive nutrient line works out to less than $2/gram? Add in recurring expenses such as the electric (and water) bill, CO2 tank refill, etc. and the cost to grow is still extremely low compared to current prices. I wouldn't factor in any expense that is related to "stealthing" the grow as that is based primarily upon cannabis' current illegality (and secondarily, on a person's living in an area where they don't feel that it is safe to leave their doors unlocked at night - and that's not the cannabis' fault, lol). Bulbs aren't that cheap but factored against the amount of product that they will produce, it's a small expense. Most equipment lasts years. Genetics - if you do not already have them - are not a negligible expense, but again this is something that will last for years (or indefinitely).
The single biggest expense that non-growers are paying for is the balls of the person who is willing to do something that is illegal.
Will it? I imagine that it will increase, but I am not too sure about the "dramatically" part. I know plenty of people who do not grow because of the current laws but I know VERY few who choose not to consume because of them.
They just get it from somebody else who is willing to take the risks, and they do pay a premium for that.
For now.
A little birdie told me that there are sites that will help even the most inexperienced newbie learn to grow his/her own high-quality cannabis. Don't look now, but we're posting on one.