In Alistair Reynolds' Revelation Space universe, there are mentions of the "Americano era", which was an earlier attempt to settle star systems in the way you d

In Alistair Reynolds' Revelation Space universe, there are mentions of the "Americano era", which was an earlier attempt to settle star systems in the way you describe. The Americano civilication crashed in one generation because growing up without parents, a higher percentage (I think ~2-3%) of people became murdering psychopaths. That such people would be off their rockers is a plausible hypothesis, but fortunately no-one's tested it.