Tobacco does have its limits age-wise, as many a smoker of pre-Embargo Cuban cigars has discovered.
(Not always, though...years ago I had a chance to sample a 1905 Partagas. A remarkable experience.)
Again with the Cubans; I gave up on them years ago. People are so fixated on them, which is why 90% are fake and yet they sell to enthusiastic buyers.
Like everything that is manufactured - especially handmade things - quality of Cuban-manufactured cigars and Cuban tobacco can vary.
There is the very best, the pretty good, the ok and “everything else”.
Just because a Cigar is made from pre-embargo Cuban tobacco that was found in a warehouse and somehow acquired, IMHO there is no guarantee the resulting cigars will be the best of the best. I’ve had a few “pre-embargo” and they were nothing to write home about.
Like any product that is aged, the quality after aging is first limited by the quality of the raw material before aging. In the same way that JFK made sure that he had stocked up prior signing the embargo, if that “mystery” tobacco had been of superior quality, it would have somehow “disappeared” at the outset and been made into cigars. IMHO, only lower quality tobacco would be abandoned in the face of a coming embargo, especially if there was a large quantity.
IMHO, the best Cubans are in a class by themselves but they’re a very rare treat.
On the topic of aging, regarding non-Cubans, starting at about 2-3 years properly kept in an Elie Bleu humidor even a rather standard cigar will have a dramatically better taste compared to the day it went in. Aging really brings out the best of tobacco. There are some smokers who smoke long-aged cigars exclusively. But even the Elie Bleu can not make a bad-tasting tobacco taste good.