Yep, this is one of the big downgrades for the pm-NW elites who was used to the companion upgrades clearing with them at the 5 day mark with other plats. With United upgrading their program this year to give companion's matching upgrade elite level, I'm hoping this pushes Delta to eventually match AA and UA's companion upgrade benefit.
As it is now, a PM/DM has very slim chances of sitting upfront with their companion (I can't remember the last time I was on a flight where all elites cleared and flight went out with first class seats empty).