On the contrary, advertising will flourish even more.
It seems that everyone can agree that there is a type of advertising which has as its main function to affect a person's subconscious tendencies toward a particular brand.
Now, if every brand employs this sort of advertising, to a more or less equal degree, then
exactly which brand does a person settle on? If the advertising is done right on each brand's
behalf, then statistically there will be roughly equal portions of the consumer base that will
prefer any particular brand. Any new brand that enters the fray will be at a gross disadvantage
unless they employ similar tactics. It will become economically impossible for them to sell their
brand name product without a comparative advertising campaign. Also, if any existing brand ups
its advertising effectiveness, then the other brands will have to follow suit, or risk losing
large portions of the consumer base. So you see, more and better advertising begets more and
better advertising, and a vicious cycle ensues.
More advertising agencies will emerge to handle the increasing volume of required advertising.
These agencies will compete amongst themselves (through advertising) to be employed by the
various brands. Existing agencies will need to increase their output further, too, and so
advertisers will begin to pay other advertisers to advertise their advertising!
Eventually, we will reach the advertising event horizon! -- where it becomes economically
infeasible to operate any business other than an advertising agency! Civilization will collapse
and any subsequent civilizations will have archaeological sites dedicated to the "marketing era"
strata of the earth's crust.