Because the shortage system is just badly done and allows a lot of abuse.
If there is a shortage, just buy/sell a small amount to cancel it for a month.
An insignificant deficit compared to its economy generates maximum instantaneous penalties, which is both annoying and handicapping, more than it should be compared to the size of the deficit.
So that would have been an opportunity to improve the system, which can be very interesting and relatively simple, without really having to reform the economic system, just improve the scarcity system and take advantage of it to enrich the game.
Shortage - Prosperity : progressive