Just to add a couple more comments. The '4%' ia an eyeball grabbing ploy and very misleading in that it suggests one would have had to be in the 4% of 'total wealth generating' stocks in the U.S. market in order to make a reasonable return.

That is nonsense. The slight of hand that is occurring here is that 'the other 96% of stocks in aggregate only generated a return equal to 1 month T-bills'. Note the 'in aggregate'. The reality is that over 40% of the stocks (and higher percentages than that in many periods) generated returns in excess of 1 month T-bills.

So no, you absolutely do not have to find that 4% of the biggest winners - there's a far larger pool than that from which to reap good returns.

It is a shame that university profs have to resort to National Enquirer type headlines to attract attention.