I think cart work will come back but I do wonder if this is their cue to go into full on "isolationist" cult mode. It's the ideal time to smuggle in dropping the door to door work under the radar.
Ok We already know they're a cult but at least they have some, albeit nominal, contact with the public around their religion, with the potential for meaningful discussion.
That's where the danger lies for the GB as many people are now aware of watchtower's failings
E.g. a couple years ago a young-ish woman knocked at my door and I was able to tell her about the UN scandal. She was shocked. She had literally no idea.
This isn't so likely to happen with cart work because people rarely approach. So it's ideal for watchtower, because it gives the appearance of preaching without risking JWs having to answer some tough questions or being given the facts.