I really doubt that you have lost 2 years of use, but you have lost some because they weren’t ever used. Waxes in the tires migrate from inside to the outside with use to prevent drying out.
I would complain to the seller that you didn’t get “new” tires. See what they say.
Stories abound here how so and so got 10 years from a set of China Bombs, while someone else only got 2 years and on and on.
Kip
2015 Skyline Dart 214RB
2018 Silverado Double Cab 4x4
Andersen Hitch