I have to admit, I'm pretty bummed by this! Most of the US airports I fly through are NW/DL routes and after taking a quick look through most domestic terminals in the US, it seems a good portion of PP lounges are NW/DL. I am just a lowly NW Silver, but fly enough all over on other airlines, so I don't have enough for FF lounge access.
Does anyone have any inside info on why this is happening and whether it is on the PP side, or the airline side? I feel like I just lost the value of my membership, unless they have some trick up their sleeve to replace all of these!