The Wealth of Nations is more of a philosophy, than a prescription. That is why it is not liked today. It requires thinking.
The thought of an uncontrollable “Invisible Hand” is an anathema to modern thinking. Heck, we can control the climate now.
By contrast, what I would describe as the single greatest failure and defect of Keynes work is inherently a philosophical failure. In essence he failed to realize that in time all anyone in politics, and many in “economics”, would hear of his prescriptions is “spend”. They would heed his words about priming pumps in bad times but be deaf to cutting spending in good.
IOW: all those in government know of Keynes is that bad times demand more spending yet good times are an opportunity for more spending. The one constant is simply “more spending”. I’ve called such people “Keystone Keynesians”, and they are the ideological ancestors of the current MMC crowd.
Economics should not be divorced from philosophy, or the study of what it is to be Man, simply because economies here on Earth are human endeavors. To fail to understand human nature and how people will eagerly abuse the ideas presented them to arrive at even lunatic beliefs should damn any theory of economics as spurious, or even dangerous.
By contrast to recognize and try to account for human nature, especially when people are not put under compulsion as a consequence (unlike, say, communism which is hostile to human nature), is a sign of actual brilliance and value. For such things the failures are not in first principals as these will be actually applied (such as I’ve describe for Keynes) but in simply not imagining every possible case/instance of human mendacity or Nitwittery.