Perhaps, but then no one can say that Traders are broken because players choose to horde food. (The actions of players can not cause a specific class to be broken)
But it's not choice, it's not action. They don't chose to hold it back, they just can't be bothered to give a damn. It's apathy, inaction. A lot of people just don't want to bother with food. And since automatic deals were removed, and that deals can no longer last more than 14 days, a lot of people just decided "to heck with it". As such, to Tom and the Devs, they see huge surpluses that they need to crush. Which results in massive starvations elsewhere. Not because people are intentionally trying to starve others, but because the players don't see a reason to bother putting any time into it and OOC decisions by Tom and the Devs result in other realms hurting. Morek's apathetic rural lords didn't starve D'Hara, Tom did. D'Hara was doing quite fine before the food production values and warehouse stocks started to be toyed with.
I'm not whining about Tom's decision, but you cannot say that this is the result of choices by the players. It's the result of purely OOC factors: 1) the food game being too onerous to a large part of the player base and 2) this apathy skews statistics and make it seem, theoretically, that the trade game is suffering from an imbalance in a supply/offer ratio and 3) that the apathy for food is mistakenly believed to be purely a result of its overabundance.
There were many starvation episodes in the South that were not the result of OOC action. And some OOC action that helped reduce or prevent them (population rebalance). But for the trader game to be viable, you need a buyer and a seller. Need creates the buyer, sure. But greed was seriously overestimated, and laziness seriously underestimated. Since the birth of D'Hara, in many realms, the greatest barrier to trade from important producing realms never seemed to be ill intent, but outright apathy. It's surprising how many people don't care to turn food rot into profit. Who are the buyers to trade with if most of the sellers don't care for profits and thus, don't care to sell their food?
Save a few exceptions, only formal realm-to-realm seems to be a real source of trade deals. Traders, on their own, have a tough life. And a not very rewarding one at that.
In some stances it might be true that food suppliers are often big, but not always.
The point still stands though, that things CAN be done to put pressure on these realms. Even if you don't outright war them, think of how bad it can look in some situations if you publicize to your peers in other realms how this other realm in your federation, or whatever your current stance is, is just sitting by idly and watching you starve. Will you always get sympathy to where they second your call for trade? Maybe not. Will the other realms look at that food giant as a less dependable ally? Most likely.
If you were the leader of such a realm, would you see to it that your friends are taken care of, or show that you don't give a damn about your relations with them and anyone else listening? Ignoring such public calls on your dependability as a friend can be just as suicidal.
You assume that one only ever needs to buy from allies. Sure, you can scorn them if they watch you starve... but then again, good luck without allies. However, in most cases, they can't supply enough. Are you seriously saying that when D'Hara starves, it should go declare war on Morek? You speak in general terms that have no practical application. And in any case, a realm that is starving is a realm unable to wage war.
