If it were harder to get food, there would be communities built up just around farming and cooking. If it were harder to mine resources, there would be communities built up around mining. And if it were harder to make tools and weapons, while maybe not actual communities, you've have more characters with careers and businesses focusing on producing them. Since none of these people could get very far without the others, it would create a necessity for trade and travel.
Like Spectrus said, living on your own should be hard. In order to make any measurable progress you should have to work and communicate with other people. There may be a few careers, (hunting, sewing, etc.) that a person could reasonably be expected to succeed at on their own, but even those would require obtaining tools from other players.
Growing crops or mining might be possible, but I think it ought to take longer to gather even a negligible amount, making group projects the most desirable. If you had the choice of spending all day growing enough food for the next day, or of working with several of other people to grow enough for the next couple of weeks, plus a surplus to trade, then I think even the most antisocial player would come around and learn to cooperate.
Unless you're dealing with a pre-industralized society, in real life, crops (and most other products) are produced in bulk and then shipped out all over the world, eventually winding up in stores where people can buy them for individual consumption. It may be a complicated system, but how many jobs are created in the process? And how many innovations in technology and communication were created to make everything run more smoothly? In Cantr small, isolated villages will still be perfectly viable and perhaps the simplest way to live, but in order to build a really large, booming city, the government should have to plan and work for their success, not just rely on the nice resources they happen to be sitting on top of or a handful of people doing all the work while the other citizens are inactive most of the time. Cities don't necessarily have to have good resources at all, but people willing to pull their weight and work together should be a must.
And this is already way too long, but (in an attempt to make this post look like it's on topic...) I'll say one more thing about the potato discussion: Cooked food should have a description, and the more "advanced" the dish is the more elaborate it should be. Clothes are basically useless, but people (not all, but quite a few) wear them anyway just because they have nice descriptions and hence have become something of a status symbol. If the clothing was nothing more than the boring name of the item like everything else in Cantr, I bet very few people would bother with it.
That may be the problem with food. If there were descriptions, it might be a bigger deal to buy fancier meals, or to serve them in your restaurant or bakery. Would you rather eat "a piping hot baked potato, drizzled with hot melted butter and topped with a spoonful of sour cream and a sprinkling of chives" or "100g of potatoes"? (And nevermind if Cantr doesn't have butter or sour cream or chives, you get the idea
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