The other side of the problem in coming with produce is that there is not much use producing.
once everyone has a descent weapon and armor who needs it, I have made backpacks and waterskins for everyone and I'm drowning in food and rock H effectilvly have no reason to keep up the production. The last three years all production in my fort has gone to a standstill to empty up the food stockppiles, and there is no reason to make anything out of leather or coth anymore. Nor carpentry or masonry.
I have basicly produced the finite amount of goods needed to run the fortress indefinitly. My main export is silk narrow clothing and the most common job in my fortress is dumping excess stone into the lava. to the point of keep handing out wages despite there not being that much work o do I have even built a casino the keep my dwarfes filthy rich. Those dwarfes who have not yet hit legendary that is.
The main problem in food production is basicly that the consumption is too low. Everyone is eating lavish meals, I take care of producing as many ingridients as possible so that the meals contain fish, meat, wheat, mushrooms etc. there are at least 5 kinds of booze and I have over 200 caged animals whith only the pet ones reproducing.
The main reason this is broken is that there is a very finite domestic demand. Dwarfes neither need nor want much aside a small room with basic furniture and do not ue clothes. they don't wear crafts, new clothes, demand pocket knifes once the old ones are broken and gone, they do not brake stone mugs, nor appreciate golden mugs (since they still not use them)
Once the basic needs are met (and this should be harder), there should be a demand for more goods, dwarefs should get a bad thought if they coulnd't afford to buy new stuff this month, and wages should increase if there is a surplus of production to reflect the wealth of the fortress attracting immigrants in search of a better life.
the higher the wages the more immigration you get, and the higher the wage of the individual dwarf the higher are his expectations of consumtion. Eating a lavish meal in a legendary dining room is sudenly not enaugh. He wont get a happy though unless its a masterpiece meal in an epic room with waterfall, and he will demand higher quality clothing to replace his old clothing that is put into the cabinet.
A noble will demand masterpiece giant cave spider silk clothes etc acording to the overaal level of the wages. So in a rich fort demands increases to meet the surplus. what keeps this is check in a large enough fortress is the maltusian logic. if prodution increases then so should the number of dwarfes. and since new dwarfes, may it be children or imigrants increase demand while not correspondingly increasing productivity, poverty continues to be spread amongst the lower classes. so that the middle class (craftdwarfes and carpenters) have a higher standard of living than the lower class, peasants and haulers. and the nobility have an even higher standard of living, while providing the fort with something of value. say politcal stability, give happy thoughts to dwarfes who have been talked to by a noble etc.