It may be true that advertisers believe that, but that statement (advertising to smart people is a waste of time) is not.
Buying based on brand recognition is just one facet of a multitude of ways advertising affects buying habits. There are a lot of advertisers that already have a great product, but just need to get the word out (i.e. many YC startups). From the article, "Laporte said he charges $70 CPMs for ads." Clearly advertising to smart people is in demand.