So here's what happened when UA implemented PQD while at the same time cutting elite benes . . .
First there was a bunch of talk in the UA forum about "thinning the herd" by getting rid of the "cheap mileage runners" and how that would improve the elite experience for those "high value flyers" who remained.
Then UA found they were losing a bunch of frequent flyer business, particularly 1Ks who it turned out were material to their profitability. So they "gifted" status to a whole bunch of people last year (annoying the heck out of those self-proclaimed "HVFs"), while at the same time upping the PQMs on discount front cabin fares (P and A) to 200%, which had the effect of making it easier to qualify for status while flying less.
So the ranks are once again full of 1Ks, but benefits continue to be cut, with upgrades nearing extinction.
That is the basic "loyalty" program model in 2017, and there is no reason to believe that the essential trajectory of WoH will be materially different.