When discussing aging, it is like comparing apples and oranges when discussing vulcanized tires and stitched tubulars. Aging does not toughen a vulcanized tire; the vulcanization already did that. Aging only deteriorates the tire. A “green” (non-vulcanized) tire, on the other hand, may benefit up to a point from some aging. The vulcanized tread may or may not improve, but for a while, the casing and the hand-applied glue bonds might. After a certain amount of time, though, the glue bonds will break down, and the base tape, and possibly the tread as well, may peel off.
"It never gets easier, you just go faster..." - Greg Lemond
"I enjoy climbing...I enjoy seeing people disappear behind me." - Robert Millar