A good example is R Huna’s intervention into malfunctioning food markets:
farmers were bringing food from villages and then whatever is left at the end of the week was lost. So, the farmers started bringing less to avoid losses, leading to shortages and higher prices. Classic market failure.
R Huna started buying leftover food at the end of the week to increase supply. But he did not give away the food for free – this would create a “great society” welfare system, with poor expecting handouts, not buying, and destroying the market again. Instead, he sent that food down the river – not to be destroyed, as this will be asur, but to be picked up by downstream poor who will not distort the local market.
I wish Pres Johnson learnt this Gemora …