If the GB really believed their prophecies that government will turn on religion and will seek to persecute JWs in particular, having this compound will make the GB and all the cult leadership vulnerable to capture, imprisonment, or wiping out with one missile. If Warwick is anything like their properties at Wallkill and Patterson, they'll be painted concrete "Soviet style" structures that will begin crumbling as soon as they're built.
WT is acting in direct opposition to their claimed beliefs. While they claim that everyone will be throwing their money in the streets, WT has been cashing in properties worldwide for that "soon to be worthless" cash. Instead of them growing the organization, it is in contraction with properties and branches liquidate and personel sent away in search of other jobs (nothing like dedicating 30+ years as an unskilled WT drone and getting pushed out into the world during the worst economic downturn in decades). And with so many branches closed and operations consolidated to fewer countries, if the political climate changes in countries like Germany or Canada, WT's fortunes could be quickly changed and/or taxed.