Grossingers was in Sullivan County which I considered the armpit of NY State; truly the northern reaches of Appalachia.
The resorts died due to multiple reasons in addition to the advent of affordable air conditioners. Many cultural and economic factors were in play. Many of the hotel owners had stopped reinvesting in capital improvements a decade earlier. Grossingers in the mid70s was threadbare with an early 60s look. Most hotels looked even worse.
Grossingers was founded by the revered Jennie Grossinger and run by her less competent children in the 70s. Jennie’s grandson Paul Etess should’ve been the family’s white knight but sadly left the family biz to work instead for Trumpty, and tragically died in a Trump helo crash in 1989.