Whether there is a purging of X percent of mgmt. or not, the theory is practiced.
AA and UA have just done it more recently thru mergers which still are in process and which have resulted in mgmt. cuts. AA and UA mgmt. ranks are smaller than they were a couple years ago... that is a fact. at least in the case of AA, there will continue to be shrinkage. Merged efficient companies are able to use less people. I don't know of a single function that DL is doing that still retains separate or parallel PMNW and PMDL processes or technology.... perhaps Kev or dawg can speak up if that still exists. There are many separations that still exist at AA and UA, and perhaps even WN.
And given that DL says that they are able to do it based on increased productivity, they very well could be using technology and improved processes in order to operate more efficiently.
regardless of the reason, DL has done this before and so have other companies, even while adding to frontline worker ranks.