Artist: Avant-garde artists intend their work to challenge a society' s mainstream beliefs and initiate change  And some art collectors claim that an avant-garde work that becomes popular in its own time is successful  However, a society' s mainstream beliefs do not generally show any significant changes over a short period of time
Ttherefore, when an avant-garde work becomes popular it is a sign that the work is not successful, since it does not fulfil the intentions of its creator
It provides support for the initial premise in the argument.