I'm not sure the lack of zeal is any worse than the recent past. But I think it is more open and evident.
In the past 10 years (when we were very active) there were very few JWs who could be called "zealous". Nearly all were just going through the motions. Field Service was a joke. L-O-N-G breaks. Lots of windshielding -- driving from one end of the territory to another chasing RVs that were not at home (and they weren't home yesterday either). When we were first awakening, we would go "as our family" and make one call, go to breakfast, make another call and head home. I think we thought we were bluffing the kids (all of whom were "out" before we were).
Now however, there is less "hiding" it. The pubs who watch over the carts/trollys are boring and apathetic. It is SO obvious that they are just "counting time". Everyone takes an hour-long break and no one cares (because they all do it too). Of course, that changes when the CO comes to visit. LOL
Old JWs still hope the end comes before they die, but younger JWs are planning for their futures in "this system". They show no evidence that they believe that "The End" is anywhere close. They may "talk the talk" around other JWs, but by their lifestyle none of them "walk the walk".
Building new homes. Having children. Saving for retirement. Destination vacations. Living the good life. None of that has anything to do with having a "zeal" for saving lives during this "Time of the End" -- the last minutes of the Last Days.