The economist provides a nice obituary but without quite enough annotation. The remark from Samuelson about "economics in one lesson" is a slam on Henry Hazlitt's book of the same title, which sold a lot of copies about half a century ago.
The Economist suggests that Samuelson's book was too positive about the ability of the economy to find an equilibrium on its own. Putting aside the misunderstanding of how economists think about equilibrium implicit in this claim, I would have thought that the main problem with Samuelson's text was the howlers it contained in its pre-end-of-communism discussions of comparative systems. In that regard, consider
The Soviet economy is proof that, contrary to what many skeptics had earlier believed, a Socialist command economy can function and even thrive" (Samuelson, 13th ed., page 837, quoted in Skousen).A perfect genius would, of course, be a boring genius, so we should appreciate Samuelson and pay attention to both his successes and his blind spots as we seek to profit from his example.