The rural areas I "so lovingly" referred to could well have been Ellenville or Kerhonkson, NY. They are not likely targets.
Do you really think more hospitals in an area likely to be hit by a WMD attack would make a difference when everybody leaves those areas?
If the greater New York metropolitan area has to be evacuated, where are about 20 million folks supposed to get shelter?
Closing these hospitals will have little, if any, effect on a WMD response, should one be required.
It depends on the number of folks affected, the nature of the WMD attack and how persistent are the effects. If it only affects thousands, or a few tens of thousands, maybe that would be sufficient to prevent things from getting out of hand. IMHO, it would be foolish in this day and age not to have a surge capacity for mass casualties in at least the ten largest cities in the country.
Follow all the people moving to the Mid-Hudson valley now, and beat the rush.
The other option would be to convert hospital wings into private medical suites to keep the building open, and subsidize the doctor groups' lease and building maintanence costs.
But who would want to open a practice in a run down marginal hospital? I don't know.