@George phil,
Problems seem to begin when things get too BIG. Big government just as bad as big business. Keep things smaller. Smallism not socialism. It's a trade off between efficiencies of scale and corruptions of scale.
Insurance is a special case. It's not a real business. They produce no actual value. The bigger the pool the better the coverage. It's obvious that it should be nationalized. Single payer. Banks are a similar case. They produce no actual value thus should be nationalized.
Keep legitimate businesses small. Nationalize/socialize "businesses" that produce no value.