bri1980 - well put. The 757 wouldn't be *quite* as popular now either if it wasn't for Aviation Partners - look at how many went for freight conversion before "thin transatlantic" took hold at AA, CO etc.
If Airbus put a few CFM56-5C4 from an 340 onto a 321, assuming ground clearance and whatnot, it might shift more like a 757 which after all has 37,000-43,000 lbs of thrust each side
