I am under the impression (this being before I was born) that Delphi was
most popular in the late 60's, having been developed in DoD/RAND circles.
This was also the time period that gave us the "Nifty Fifty" (why didn't
Surowiecki mention them?), the large-cap stocks of unusual growth in which
investment was a no-brainer.
Unfortunately for both Delphi and the Nifty Fifty, the early seventies
happened... Americathon, anyone? I have a great copy of Graham and Dodd
from a used bookstore: the 1962 edition, in which the authors say that
although some folk believe the business cycle dead and modern finance
triumphant, they prefer to stick to their "margin of safety" theories.
 not to be confused with the Delphi Oracle's technique, which took
advantage of a feature of Greek grammar in which it was impossible to
distinguish between the subject and object of a subordinate clause. Even
better than the Japanese structure which allows one to observe the reaction
to a sentence before adding (or omitting) the negation.
 four legs good, two legs bad .... baaaaaa ....
 no problem, if you didn't mind taking a 50% hit to even an unleveraged