Up until the beginning of the twentieth century, applause between movements and even during movements was the sign of a knowledgeable, appreciative audience, not of an ignorant one. The biographies of major composers are full of happy reports of what would now be seen as wildly inappropriate applause.
Blame for the move to silence eventually falls on the conductors, beginning especially with Leopold Stokowski:
To refrain from applause heightens focus on the personality of the conductor. Silence is the measure of the unbreakable spell that Maestro is supposedly casting on us. A big ovation at the end salutes his mastery of the architecture of the work, or whatever… By the way, IÄôve noticed a new trend ÄîThoughtful Celebrity Conductors holding their arms motionless for ten or fifteen seconds after the end of some vast construction by Bruckner or Mahler. ÄúDo not yet applaud!Äù those frozen arms say. ÄúDo not profane the moment!Äù
He goes on further to touch on the influence of recording technology on the individual & concert listening experience, the rise of classical performance as a high-brow cultural event, and the communal aspect of concert attendance.