I don't play the game much anymore because of the 38% tax rate, and the fertilizing fields (stupid flower menu).
To conduct a fair trade, hypothetically 50 silver for Sea Island cloth, which is roughly its value.
1. Fair trade 2 oil boards for 1 Sea Island cloth, 25s and 50s respectively.
2. Cloth Seller jacks up price from 50 to 82 to compensate using a stall.
3. Board seller supply high demand at 30 silver per board, you get 18s after tax.
4. Requires average of 4.6 boards 2.3 times more
This is a simple example, one sided of course where board seller is taking all the lost on the trade, as the cloth seller is taking none. The only fair trade is to the cloth seller as he is getting 50s per cloth. but it could be shared if cloth seller lowers his price. A price of 30s or 35s is still causing 2x or more cost to the board seller, higher you go of course you won't be able to sell as many and drastically slows down at 40s per board or more. My experience with 30s is they are gone in 1-2 days, at 35s it took 4 or 5 days and boards were starting to piling up. Sea Island does not sell at all at 82 silver, you have to lower it and share some of the cost of stall trading. You have limited sales at 75 silver but don't expect to sell a lot of them if you have a lot to sell. 75 isn't bad if you just have a few and if you want to stock the stall for the desperate and sell it in the 80's you could. There are some people who are just given silver so even absurd pricing is ok.
My run down score of Salem:
-1 point for annoying fertilizing flower menus
-1 for higher than 10% tax
-1 for higher than 20% tax
-1 for higher than 30% tax
-1 for causing double cost to fair trading due to high tax
-1 largest town system (lame)
-2 for not giving any information on it (I don't like hidden crap in games)
-1 for not being able to compost seeds :*(
+1 for selling mass poop on stall
Overall a negative experience, of course there are a lot of positives but in the end its is mostly negative for me

Regardless of the reasons why players leave, I have listed mine as I only play for a couple hours per week now, and eventually will not play at all. The main reason is the high stall tax, and the irritating flower menu on fields, that flower menu really makes me mad haha.
Trading is why I liked playing Salem, as well as being able to specialize and concentrate on one profession because of it. if it is costing an "effective" 115% tax, it is not fun to have all your hard work taxed away. I still hate barrel trading more than the 38% though. Back when the stall tax was lower, even then i felt it was too high, but at least i could somewhat tolerate it then.
I don't expect lower tax rate, its not the direction JC wants the game to go I think....So, all I can do is leave heh.