You mentioned gliders which were discontinued in the 50’s when the 82nd’s 325 Abn inf Regt was still a glider outfit. Since then there have been many applications where gliders could have been used instead of sending in the much more expensive, and maintainence intensive choppers. Were they a casualty of the rotary wing war ?
More powerful engines on short takeoff cargo-transport aircraft capable of using unimproved short runways while transporting air portable vehicles largely made the highly vulnerable and relatively dangerous to use glider transports obsolete; e.g. Chase/Fairchild C-123 Provider.
Fairchild C-123 Provider
The C-123 Provider was designed originally as an assault glider aircraft for the United States Air Force (USAF) by Chase Aircraft as the XCG-20 (Chase designation MS-8 Avitruc)[1]
Wikipedia
https://en.wikipedia.org/wiki/Fairchild_C-123_Provider