Paradoxically, or at least anecdotally, I can't comment on the demise of the local JW congregation in my small regional city. I'm a recent blow-in, and my arrival here coincided with the JW's post-Covid resumption of the door to door work. We've had at least one visit per year from the JWs. Just last Friday I saw not one but two trolleys/carts in town to which "encounter" I devoted a thread:
https://www.jehovahs-witness.com/topic/6545528670650368/there-some-sort-campaign-on
On a Tuesday evening, ironically while on my way to another church's Bible study, I see the Kingdom Hall carpark on the edge of town quite full. From my perspective, the local Kingdom Hall may well be in quite a healthy state. Of course, they could well be down to one healthy congregation, where once they had two. It would be great to be able to engage in the sorts of conversations that would yield such information, but I find that the JWs of today are not the robust engagers in conversation and debate that their ancestors of a mere two or three decades ago were. They disappear very quickly, drawing from my experiences with them since I've moved here.
My apologies for the above: that was a lot of waffle to basically say very little 😔 🙄