Marijuana? It's cultivation is pretty much generic, heck, I even cultivated some. You don't need pesticides, nor careful temperature, nor frankly anything. It's a very easy plant to work with (aside hemp fiber working, that's painful). Production efficiency is hard to increase because the cap is easy to reach with the plant. All you can do is to start replacing manual job for machines like in any developed country farm.
Now, why that produces famine? Manual farmers often uses better the space to cultivate (because it's hard to do details with our current machines), and cultivate food in the extra space gained for their consumption and neighborhood, along always having animal output. More advance farms just doesn't give a fuck about food security or anything as the profiter hardly lives near anyway (on gang/mafia system, the adjacent profiter to the farmer often lives there, too).
Any hectare used in a cash crop is food production lost, and because all this happens in the developing world (because hey, the agricultural % of workforce in developed countries is almost null and you're eating developing world's food right now), then, yeah, more famine as less food is produced in the already scarce terrain available. Currently the decrease in food production in favor of cash crops has made an impressive decline, the birth rates are a way higher than the increase in food output, thus more famine. At least distribution has improved thanks to the increase in infrastructure, but it wasn't being enough in stop the increase in famine. There are other factors aside cash crops, of course, but it's well known that cash crops shares a big side of the issue.
Sadly one of the few things that money can't purchase is to make food from void, so even when economical poverty reduces, worldwide famine prevails unless you sacrifice some money on food production over cash crops. Oh, yeah, cash crops are usually mean by profit maker crops, but it's also used for crops who are most the time not eaten at all, like tea, I'm using that use.
As for the Standard Capitalism thing, economically wise, thanks to monopolies, labor laws and so, it's well known it's more ineffective than gangs and mafia who just need to spend money more money in military power. That doesn't mean Standard Capitalism is bad, the Mafia/Gang Capitalism system brings a lot of social injustice, crime and so, while Standard one is importantly better for society, just you need to spend more money and you get less in the private aspect.
Hemp, while the same species, is another plant. You can't make hemp products with marijuana plants, likewise you can't make marijuana with hemp. Hemp is already legal and an industry in all the globe aside USA, it's just that hemp products sucks in cost-effectiveness and aside fibers, quality (who massively sucks in cost-effectiveness). Mostly only you see a hemp industry here on Chile, China and France (holding about an accumulate production of 96%) for historical reasons rather than economics, mere novelty and niche markets. Speculation says that marijuana seeds from hemp are already being sold in the illegal market, and those who doesn't, well, oil and other products, marijuana seeds are not illegal outside USA. Hemp's unique positive point in economics is it's low intensity capital need, but aside that is pretty much uncompetitive.
As for the marijuana>alcohol, lel, that's subjective, but I don't think you'll ever see that, nor an outstanding increase or anything. It's a mere opinion, though, but marijuana users aren't very loyal after a few years because it doesn't produce addiction, and that's important for a drug to be an omnipresent success.
I still think that the market
already exists (
or newest) rather that it's about to be created. It's massive of course, the most harvested crop in weight and profit in the world (though all alcohol crops fused are various times higher).