the costs of the caravan which are only food and beer (no money involved) are trivial even if it was to the furthest away island on the edge of the map.
The costs of sending a caravan... of wagons... across the entire world... "are trivial?"
Ermmm
Okay, let's give it a shot. The cost of a caravan:
1) A good dozen or so dwarves, occupied for months at best. All of those dwarves could be doing other things, like mining and brewing and armoring, or defending other settlements. Thus the cost of not having them around is equal the the added value of
ALL the goods they would have produced and possibly even the loss of other settlements if those guards had been there to defend houses and not wagons. A dozen dwarves can produce/defend a lot of value in that time.
2) Whatever the chance is that the caravan will be lost, multiplied by (the entire value of everything in the caravan PLUS the loss of any aid to the target settlement PLUS the entire lifetime production or protection potential of every dwarf in the caravan who dies (i.e. several times the value of #1)). And anybody who has played adventure mode for 10 minutes can tell you that the chance of losing a caravan going across the whole world is probably well above 50%, both ways, if we're being honest probably higher.
3) The strategic disadvantage of your enemies (bandits or enemy civs) getting control of all of the stuff in your caravan, multiplied by the chance of it being lost.
4) The cost of operating the caravan, which is food, booze, spare parts, ammunition as expendables, as well as a large overhead cost of equipment and outfitting, which you hope to get back but still have to spend initially (and risk losing), including all of the dwarves' clothing, armor, weapons, the wagon, and the livestock.
5) The potential loss of a skilled diplomat/noble, which presumably is seen as a much greater loss to the mountainhomes than other dwarves. Also, that diplomat is occupied for months, stopping him from performing other valuable potential duties for the realm like negotiating with hostile nations, which is an opportunity cost.
5) If the caravan visits multiple settlements, then the risk gets higher, because they stand to lose even more goods (if it's for profit) or they stand to endanger more settlements through no resupply that year (if it's supporting them).
6) The very significant cost of ships and crews and the additional significant risk of sinking for caravans that cross bodies of water, OR likewise additional huge costs for pack trains, sherpas, whatever (or mining crews if tunneling) to cross mountains.
A caravan, just like in real life, represents a
HUGE investiture for any real distance. One that
is proportional to distance though. A "caravan" to go 5 miles down the road is no big deal. You probably don't even need guards, etc. Whereas one to go to an island on the other side of the world might be a massive drain on the national treasury (considering they'd probably have to send out like 10 of them to ensure one gets there, and fleets for each one... and 100 dwarves' lives at stake, blah blah).
Countries simply do not send expeditionary forces across the world just to sell some random pig farmers living in a hole in the dirt some old rags, purely because they're there... Nor would the mountainhomes pay 150,000 dorfbucks for such a mission only to have the trader when he arrives haggle with the inhabitants over 7 or 6 bucks for every piece of cheese or whatever. That's plain silliness.
WHETHER they send a caravan to you should depend on your strategic value (military strength and economic potential, possibly many other things as game features are added to let players interact beyond their forts more) and/or your expected goods profits, compared to your distance. And if your strategic value is a lot greater than the cost of the distance, then they should be quite willing to invest the leftover funds for such an important strategic fort by giving you more resources that you need to further the cause.
Basically:
* Calculate the caravan as if it were purely for profit (like human), including distance.
* Now consider the strategic value of the settlement, and consider a proportional amount of the costs subsidized. If any strategic value is left over, begin subsidizing the goods in the caravan as available for free when it arrives. If more strategic value is still left over after THAT, begin signing up the members of the caravan to stay at the settlement as migrants, or brining a cashbox, or other things.
* If the strategic value + the potential commercial profit is not enough to cover the cost of the trip, you simply don't get a caravan. UNLESS you have a taxation model, in which case, taxes you plan to extract from the settlement can help cover the cost. But even then, if taxes + profit + value don't = cost, still no caravan.
It is in the Civ's interests to grow, expand and survive. Historically they did so, which means they have rejected the kind of logic that your expound. If nobody ever subsidised the outlying areas, then no civilization would ever have expanded.
What logic? I never suggested otherwise.
What I said was that the value your settlement holds to the mountainhomes can be calculated as your strategic value to them, but it is NOT a function of distance from the capital. A gold mine 20 feet away from the capital is for the most part just as valuable as a gold mine 100 miles from the capital (or might be less or more). And a military output at a major river junction 200 miles away might be equally as important as a mountain pass fort 10 miles away (or less. Or more).
Therefore, it is illogical that the subsidies they pay to help out their forts would be dependent upon distance, which they are under your formulation -- you're saying they should only subsidize the trip, not any goods in it. Since a trip's cost is very much proportional to its length, this is just another way of saying that subsidy = distance from the fort. But that does not make sense. Subsidy should = strategic/commercial to the mountainhome, which is by no means the same thing, and is unlikely to even be correlated to distance.
money stuff
Okay sure. I disagree about several things you said about money here, but since it wouldn't hurt anything done the way you suggested, it doesn't really bother me. If people want money like that, go for it. Not worth arguing about.
The game would give you a warning if you tried to order coin production without permission (if your civilization's central governement claimed sole authority). If you coined currency anyway, you could get away with it for a while, but eventually your civ would someone to inspect for the source of counterfeit money.
Fair enough, that does actually sound amusing. Though the novelty would get old after a couple of times and become just sort of a cheap obligatory trick to do for some certain amount you know you can get away with. Which soudns tiresome, but maybe there's a defense of some sort against that.