Doug Engelbart, who invented the computer mouse, did not make much money from his invention because its patent expired in 1987, before the surge in demand for home comupters. This fact poses a problem for people daft enough to think that markets reward merit - because it's quite common for very meritorious people to fail simply by being ahead of their time. Let's take a few examples from different fields:

- Kane Kramer invented the digital audio player in 1979, far too soon for it to become sufficiently useful that he could profit from it. George Gray's patent on LCD screens expired in 1993, well before the explosion in demand for flat screen TVs and smartphones. Nicholas-Joseph Cugnot invented the car in 1769, and lost his reward for doing so in the French Revolution.

- Many writers died in obscure poverty before they reaped the rewards to their greatness: Melville, Poe and Fitzgerald to name but three.

- At the peak of his prowess with Blackpool in the 1950s, Sir Stanley Matthews earned £25 per week. A player of his ability today could get 10,000 times that.

- Many musicians died before their talent was recognized. Nick Drake, Jeff Buckley, Eva Cassidy and many great bluesmen sold about six records between them during their lifetime.

To put this another way, to achieve success it is not sufficient (nor necessary either - but that's another story) to be brilliant. You have to be brilliant at the right time. So, for example, if you'd forecast the financial crash in 2005 or 2006 and traded accordingly, you'd probably have lost money and been a failure.

I suspect that, in many walks of life - the arts, business and finance - financial success requires a one standard deviation intelligence. Writers must be sufficiently smarter than their readers that readers feel their intelligence to be flattered, but not so much smarter that they appear weird. Investors must buy or sell ahead of the pack, but only slightly so, else they'll lose money waiting for others to catch up. Businessmen must anticipate what customers will want tomorrow, not 10 years hence.

The point I'm making here is simply the obverse of that made by Malcolm Gladwell, who's pointed out that most of the richest men in US history were born into two periods: the 1830s and 40s, and the mid-1950s. They were born at the right time. Others, however, brilliant, were born at the wrong time. Which is one more reason, among many, why markets don't reward merit.