The bay of pigs invasion and the red scare were attempts to stop communist ideology from spreading. This was done in order to perpetuate and protect the status quo in the USA for geopolitical reasons, but is not necessary for capitalism to function. Many nations start conflicts with each other because of a difference in ideology, and a perceived need to contain or counteract the ideology of the other nation, and this is not limited to capitalist societies. The USSR for example engaged in many conflicts with its neighbors in an attempt to export the revolution and spread its influence. Yet I wouldn’t say these conflicts were necessary for communism to function as a system, any more than the conflicts capitalist countries engaged in were necessary for capitalism to work.
I disagree that capitalism is not a natural state that things can revert to. I believe that if you were to take a random sample of humanity, wipe their memories and drop them on an alien world, capitalism would happen. Not because there’s a “system” making it happen, but because that’s just what people do.
I appreciate the recommendations. I’ll check out Pëtr Kropotkin.