JOHN MAYNARD KEYNES IN 1926

His short essay "The end of laissez-faire" is today still worth reading, not least because he mentions problems for cartoon capitalism:

For economists generally reserve for a later stage of their argument the complications which arise - (1) when the efficient units of production are large relatively to the units of consumption, (2) when overhead costs or joint costs are present, (3) when internal economies tend to the aggregation of production, (4) when the time required for adjustments is long, (5) when ignorance prevails over knowledge and (6) when monopolies and combinations interfere with equality in bargaining - they reserve, that is to say, for a later stage their analysis of the actual facts.

Since 1926, psychologists have gradually built up an huge amount of evidence that shows ignorance all too often prevails.  As a result, even economists now admit that the "standard economic model of human behavior includes three unrealistic traits—unbounded rationality, unbounded willpower, and unbounded selfishness."