PIMOs may be able to hang in longer if the WTS's struggles get bad enough. They could reach a point where they just want the numbers to look good while they try to keep the ship from sinking. In that case, the pressure would ease on those who are not doing enough to avoid scrutiny.
As for me, I was barely able to keep up when I was PIMI. I can't imagine being PIMO and having to schedule so much time around the meetings and field service, or trying to convince people to study with the JWs when I do not believe in it myself. It's a bridge too far for me.