I agree with you, the movement to the DC3 initially, was a move to sell more seats to make pax flying profitable - read losing money on smaller planes. Aircraft size has continued to increase at every turn as legacy carriers needed more and more pax to dilute fixed costs. That trend hit the skids with the intro of the 747 which lost money because there was not enough demand to fill them. The cost of travel continued to drop because the industry became more and more efficient. Of course 15cent fuel in the 90's helped keep costs down. The mega leap in fuel prices have brought this to a head - no gradual rise to make an adjustment to.
So, if anyone here thinks the DC3 should make a comeback to the majors - plz speak up.