ALCARLOS,
I completely agree that there are markets and/or times of day that don't have the demand to justify using a larger plane. To me, at least, that has never been the issue (although I often wonder where all those passengers went at places like FAY, CAE, AVL, etc, that used to fill a 727, since those markets supposedly will only support turboprops/small RJ's now).
What I do question is using RJ's between our largest hub (CLT) or 'premier' hub (PHL) and major cities. For example, US West flies nothing but mainline metal between PHX and IAH. East, on the other hand, has nothing but Emb-170's between PHL & IAH while using nothing but CRJ-900's from CLT to IAH. The same comparison can be made in other markets.
Methinks dio is right - previous management was more interested in getting rid of mainline employees than they were in lowering "costs", leaving current management in a bind equipment-wise.
Jim