Sadly, I get the feeling the new producer just doesn't understand the player mentality: Second best isn't worth getting. He envisions newer players spamming reives for bayld, doing skirmish and naakuals to get better gear, and finally doing delve. But what's actually happening is players just jump immediately to delve: It has the best gear, and that also makes it the easiest to recruit people for.
While that's pretty much the crux of the issue right there, another major contributing factor is the fact that the cost of entry for Skirmish/Naakuals was just set way too high, deterring repeat runs to actually get the desired equipment, whereas it's incredibly easy in comparison to get into Delve.

While at the time, the cost of entry seemed somewhat justified due to the comparatively high tier of the equipment dropped, nowadays nobody can see the point of it if they were just going to outdate all of it with Delve in a month.