There are syndie 9-noon shows that don't do a Harvey break, right? I haven't checked Laura Ingraham's clock, but I don't think she accounts for the 11:45 hard break - stations could certainly time their way up from, say, :42.
Beck and other shows that do, do so to make it easier for Harvey affiliates to carry their show...since just about no non-all-news talker does a long noon news block in 2009.
To answer the other question, yes, I believe at some point, these hard 11:45 breaks will go away. I don't think it happens immediately following Mr. Harvey's exit from the airwaves, whenever that will be...I think it happens when it becomes apparent that any replacement won't last forever.