In the period from 1945 to the present JWs have grown and stagnated in the western world against the backdrop of mostly peaceful and prosperous world conditions.
I have a feeling this will not be the case between 2024 and 2034. Whatever growth or decline JWs experience in this decade will be dictated by seismic world events, whether that be political, social and environmental upheaval, world war, or run away technology. JWs could either thrive during a period of immense disorientation, or they could be swept away by the tide of events. In either case I think there will be more important things going on and to worry about as we find ourselves living in the curse of interesting times.