Why was the multi image technique abandoned?

Some cinematic innovations come to be accepted aspects of film grammar, often evolving to suit the styles of succeeding eras. And after doing so, some of those will, in time, fall by the wayside. Others, perhaps perceived as too boldly innovative, are quickly discarded as gimmicky, trendy and/or distracting and, having been so abandoned, are cited by later viewers as "dated" styles.

The Thomas Crown Affair, released several months before The Boston Strangler, also employed multiple-image montages. 




In 1972's Sisters, Brian DePalma pared it down to a two-panel split screen to show concurrent events, sometimes the same ones from two points of view. Although more modest, it too overstayed its welcome by extending longer than it needed to. 

Perhaps, in the end, audiences found the technique a bit too visually chaotic and overwhelming.