If the rubbers are in a vacuum sealed container, they should stay good for a long time. If oxygen can get at the rubber from any angle, the oxygen breaks down the rubber molecules over time.
After 2 years there will be a moderately small, but noticeable difference. The main differences will be that the sponge and topsheet lose some elasticity and grip. They will still be playable though.
After 4 years, it will be more noticeable but still playable. After 10 years, the rubbers won't play well.
The reason Yogi said you would notice a difference for ESN rubbers within 4 weeks is: most ESN rubbers have a factory tuner added which wears off in about 4 weeks. It evaporates and wears off whether you play the rubbers or not. But if you are used to those rubbers after the factory tuning is gone, they after that, they will deteriorate kind of how I said.
And, in a vacuum sealed package, free from oxygen, they should stay how they are as long as the vacuum seal keeps the oxygen out. That also should keep the tuning from evaporating.
But can any of us get our hands on a true vacuum sealed packaging that we can place something in and remove all the oxygen? Not that I know of.
So the info is more for the fact that, what causes rubber molecules to deteriorate over the long term, if you are not using the rubbers, is OXYGEN.
Think of a rubberband sitting on your shelf. If it is 5-10 years old and you try to use it, it will be more brittle and tear instead of stretching.
The quality of rubber in TT rubbers is much higher. But over time, that will slowly happen to the rubber in your TT rubbers as well.
Still, I have some Sriver rubbers from 1991. They feel terrible. They don't grip the ball. They feel like AntiSpin to me. But to a beginner, the beginner might not know the difference. It would feel like a recreational racket's rubbers.