Because it's not a good look.
When I track the peak player numbers, I look at like for like, a Monday for ex is not a good comparison to a Saturday, so comparing Saturday only numbers NW lost about 100,000 PP count, from 9th to the 16th, so it will be interesting to see where tommorows PP count falls, particulary in light of the broken economy, gold dupes etc
There's a still a hell of a lot of people playing though, problem is it looks to be in a cycle of one broken aspect or exploit after another, each compounding on top of each other, and whether AGS can out-run the bugs while holding onto players, as they near the end of the hype phase, fewer new players starting, more players hitting 60 and finding there's no end-game, and people generally getting to later levels and then getting bored.
They released this at least a year too early, are they competent enough to fix it and add enough content? I don't know. It's basically surviving because it's Amazon, a small dev releasing this game as was, would be well on the way to a dead game by now, NW is nowhere near to that though. So they have the chance to turn it around.