If you buy workshops in the wrong place where raw goods are expensive price for the trade good is low, yes.
Imagine if in real life, every investment was guaranteed to be profitable, money would lose its meaning.
You should not be able to finance your warmongering with 5 workshops and some odd caravans, maintaining an army was(and is) hugely expensive. Also what's the point of bandits if they don't harass caravans and hurt the economy(although I agree it needs tweaking?)
There is a difference between making no money at all v.s paying upkeep v.s profiting.
Take my pottery workshops as an example.
The city has 2 villages providing it with clay > I check the sale price of clay in the city 12-15 denars and pottery were selling for about 100-120 denars a piece > I purchase a pottery workshop > make 350-450 denars a day once it stabilized > Nerf incoming > they said they fixed an issue where 1 clay produced 2 pottery (I assume ok my earnings will be halved with a 20% fluctuation) > Nerf also says suddenly Pottery will now be halved in demand > Play my file and watch my daily earnings go from 450 max to 25 denars a day.
Most people playing i think are paying attention to available raw material before investing in a workshop and just making a logical choice of low price materials, decent town prosperity, relatively safe location, produced product has a decent price but thats not how it works apparently.
I'm all for workshops not allowing me to have a 100 plus stack of max tier units and allowing me to break even maybe a 300-400 denars in the red but it shouldn't be this bad.