Invest in weed!

If viewed as one crop product (or four, grass, hash, oil, growing seeds) of a hemp industry then obviously legalisation, even if not much tax was involved, is only going to lower prices to some degrees.

People are still going to need to produce F1 seeds if they are going to be crossing plants that result in hybrids. Places that traditionally grow specific types of bush and produce specific types of hash, are actually more likely to make more money from a legal market share - and better yet, on a fair-trade basis.
It is as you say similar to drink - sure, you can grow weed to varying extents much more easily than you can have a vineyard for wine, or a whisky brewery, but there's always going to be 'markets' for products as outlined above.

Legalisation for example would mean I'd be able to grow in ways I cannot do right now. However, I would still be wanting to buy hashes from around the world for example - as even if I had a field to grow in, it isn't the same! It's like wines, they taste different grown in different places and produced in different ways.

About tobacco - there are varieties available that don't have those 200+ toxins added and are also grown without chemicals; I've been buying them for many years. However, like with food, if people insist on buying the toxic versions then that's what the shops are going to stock, because that's what agriculture and food preparation industry is going to produce.

Of course...which is why you should never post hopped up on cold medicine...I phrased that last part completely wrong and it didn't even occur to me. I should've said:

The irony is that the last time we needed to end a great depression we ended prohibition, but I doubt very much that that will occur this time. Politicians wouldn't have the balls...it will happen eventually, but not anytime soon.

While I always think that a market will exist for premium herb, much like for expensive cheese or wine, it is very true that the price for the majority of stuff may decrease. However, how much it will decrease by is debatable. I wonder if anybody has any data on the extent to which alcohol prices dropped after the end of its prohibition, because when I go into a club or restaurant it's still expensive as all hell. Agricultural products aren't that cheap these days either unfortunately. Plus people are already accustomed to paying inflated prices...I'm not sure how much prices would drop initially, but my guess is not by much until competition sets in. I'm also skeptical of the quality of pot that would come out of an industrialized system. Look at the quality of cigarette tobacco.

My bet would also be that if it were legalized it would be taxed so heavily (thus bringing us out of a recession, but also because that would be the only way politicians could discourage its use) that prices would remain similar to that which existed on the black market for store bought stuff.

Anyway, if a commodity market is ever established for pot I'd be the first one to buy into it.

The end of prohibition would make cannabis much much cheaper(as you acknowledge). The energy intensive indoor grows would become a small boutique segment of the market like expensive artisan cheeses. The larger share of the market would move, to one degree or another, towards being a commodity like other agricultural products. So to invest then call for a change in the law is not be a good investment decision, however right it is.