I did not want to reply to Jolanthe in the other thread, but as usual when I point at something as being a problem I tend to have a solution in mind.
My preference would be to stop treating commodities as being the end result of the economy. The quantity of them should not be an indication of how well/badly things are going, because they are essential to gameplay. Without them the game breaks.
Quick solution: 1) Set all villages to have a flat sell rate of all commodities they sell (not affected by buying or doing comm quests), and 2) Give villages an infinite number of comms to sell.
What does this do? It makes comms a consistent, persistent gold sink (instead of dumping gold into org comm shops you are throwing it out of the game). You can make prices higher than what orgs are doing if you want, and let orgs with supplies / income sell theirs cheaper if they want, but there will never be an issue of actually running out.
1) Give all comms a price range. Every month each village rng rolls its pricings to fluctuate them. Set the supply to 500. If it all gets bought out, the village is restocked with another 500 and the price increases by 20% (until the next month change).
2) Only commercial governments get passive tithes from villages.
What does this do? It makes orgs choose between comm generation or power. It makes comms something that good / active trade ministers might run around on shopping expeditions to stock up their central depot when prices are good, but also keeps people from ever running out of basic necessities.
Could easily do more tweaks as necessary, but this would completely reposition commodities into a gold dump instead of a limited resource that needs to be doled out as miserly as possible to ensure that any remain at all.