Several good questions raised.
MNJRutherford, you're right that rice is cultivated in the USA. Only a few sunbelt states, though, such as California, Texas, and Louisiana.
You are also right that rice is not aquatic. This is complicated and I am not sure I fully understand all the issues myself, but my understanding is that rice is not fully aquatic, but just very tolerant of flooding, and the reason for flooding is not that the rice absolutely requires it, but to flood out pests and diseases that would otherwise build up from rice being grown in the same fields year after year after year for a few millenia now.
There is the problem that rice seems to be tropical in origins, and has never adapted to very high latitudes. Doesn't even tolerate all that much altitude. When looking at what the limits are for upland rice, I read websites saying things like "even grows in the central valley of Nepal". Well, fancy that, it's only 4,000 some feet elevation, extremely sheltered from cold fronts by the Himalaya, enjoys a subtropical climate where Eucalyptus and Caryota palms are fairly common, and even then, because of the cool summers, ripening takes longer and pushes the limits of the growing season.
I've heard of rice varieties that supposedly grow in places like Manchuria but the dominant staples are wheat and potatoes and any rice production that really exists there is probably marginal. And that despite hot (but too short) summers.
Rice also has the issue of requiring de-hulling. In Asia they have small-scale de-hulling machinery for small farms but I think it would be hard to get some here.
(Barley is usually hulled because beer-making does not require de-hulling, but there are hull-less barleys in existence).
If you happen to live in rice-growing regions, go ahead and eat it, but I suggest having backup staples. That's true too of imported rice.
I suggest eating corn, sorghum, and, if you're in a suitable climate, wheat, though wheat is laborious to harvest without a combine, and it's disease-prone.
Steve is too far north for crops like corn and sorghum to be practical, which is why he is eating barley instead. Barley is easy to ripen.
One nice thing about corn is that the whole plant is easy for humans to work, with only simple tools like a curved knife, because of the size of the plant and the food part being a convenient size and distance from the ground. Some sorghums have the same feature, with the grain all being concentrated on a head that sticks up for easy grabbing and cutting (alas, too, offering a tempting target for birds, which is why I sought out a bird-resistant type). Doesn't thresh perfectly clean but I doubt that is an issue.
Synergy, I'd like to address the point you made about cocoa and coconut, because I had the same concerns. Apparently cocoa production is very centralized in the world, with most production centralized in Africa (despite being of New World origins), and much of that in the single country of the Ivory Coast. Due to political upheavals, farmers fleeing their farms, and economic sanctions, production and export are collapsing.
It is worth noting that Hershey Chocolate company has been lobbying the US regulators to allow artificially-flavored, artificially colored hydrogenated fat to be marketed as "chocolate" in the USA. THIS IS COMING. It's already here, insofar as a lot of cheap "chocolate" imports are not made of real chocolate. This coming Easter, take a closer look at a lot of the chocolate bunnies; virtually all of the imports from Asia are not really chocolate even if they say they are.
Carob is not a substitute because for one thing, it doesn't really taste like chocolate--it's just sweet and a vaguely similar color (not really...). Carob tastes like Carob to me. For another thing, it's even rarer than chocolate. There's not a huge production of the stuff. Adult trees will tolerate brief overnight frosts but young seedlings extremely vulnerable to cold. A grower in Oz lost his entire plantings of seedlings TWICE to brief mild radiation frosts such as are common there. Plus you have to sex the seedlings, maybe do some grafting, etc. It's a great crop for semitropical deserts too dry for other crops but there's not enough production to replace chocolate.
Not to mention it's missing the KEY ingredient of chocolate: Phenylethylamine--that's why people binge on chocolate after love affairs end or after they've had a bad day.
I suggest that chocolate consumption is going to go into long-term decline, due to supply issues and costs.
Outside of the tropics, where it is still a common item, Coconut was on the way out much faster than chocolate. I don't know why, other than supply and demand seem to be out of whack. I bought some coconut fat as a source of naturally saturated, non-hydrogenated fat, and it was QUITE expensive. I had to get it mailorder as it is very hard to find anymore retail except in very small quantities (in tiny jars) at screaming prices.
It might partially be due to demand for non-hydrogenated vegetable fats have soared ever since people figured out what trans-fats do to their arteries.
I suggest simply doing without.
Steve is too far north for crops like corn and sorghum to be practical, which is why he is eating barley instead. Barley is easy to ripen.