.... if five years is as long as DL agents -- who have never worked for NW -- keep sending calls over to "Northwest" to resolve a matter, then the expectation is what it is.

You should see how messy it is when DL is operating out of multiple terminals at some airports and then informs DL customers to check in at one terminal but fly out of another. When they get it wrong, I'd expect the following to be more common than even usual: more upset, exhausted and/or late customers; and more delayed/lost/stolen baggage situations.

Perhaps AF-KL had it right in going with a holding company structure that would actually spare customers some of this confusion that has been striking DL-NW customers and even the company's employees (making it worse for customers).