This past year I sent data tapes stored in my attic for over 23 years to a gentleman who still has a reel to reel 9 track. The tapes worked perfectly.
Considering my attic is on the temperate U.S. East Coast with Summer hot and Winter cold and high humidity, something must have been wrong with Boeing’s storage standards.
This guy charges 50 bucks per reel to transfer a reel to new medium by the way: