[javajosh]

There needs to be a word for when someone does something bad in their own interest, and as a result the wider society degrades far more than the individual profited. Corrupt anti-corruption officials, yes, but also college professors issuing passing grades to customers, er I mean students, news networks that give in to the urge for sensationalism and ideologically driven attention, lawyers who escalate conflict for profit, and so on. The individual act is (relatively) harmless, but over time if left unchecked these acts degrade institutions and eventually society itself (or confidence in society, which is the same thing). These actions cause a society to move from the good nash equilibrium to the other. A healthy society can endure a certain amount of malefactors, has an immune system for them ranging from "stink eye" to "prison", but when the violations gets higher than a certain threshold, across a certain number of industries and institutions, when the immune system starts failing to catch even a fraction of it (or the immune system degrades completely), the host society begins to weaken and the majority of the herd flips from "cooperate" to "defect".

How about "enshittifiers"?

[bbwbsb]

These are positive feedback loops. Perhaps "anti-social runaway" would be a good description.

[gosub100]

Remember when Greece went broke 10+ years ago? Apparently no one was paying their taxes because they looked around and saw no one paying their taxes. It was a contributing factor because it impaired the nation's ability to get loans because it lowered the government revenue.

https://en.m.wikipedia.org/wiki/Greek_government-debt_crisis

[bryanlarsen]

I believe one standard term is negative sum games. The losers lose more than the winners win.