No one can know for certain how long their ‘cult compound’ could be around
When testing of nuclear weapons was carried out on certain pacific islands in the 1950s, it was noted afterwards that the only animal life left consisted of cockroaches, and "rats the size of cats" (to quote an original report).
I rather fear that the JW cult will prove to be the same - i.e. come what may, it will continue to survive. (Evidence of course of "Jehovah's blessing"!)