An educated buyer "MAY" buy the older Oyster if you will over a newer boat, such as the Grand Soliel or Jeanneau. "BUT" an educated buyer may not want an older hull shape or form if it is say a racer built and designed under the IOR rules vs newer hull forms with better performance and sea kindlyness < if this is a word?
Personally, I do feel a better built boat if you will, will age better, this of course is assuming both get the same maintenance. As an Oyster built with solid wood will be better than a plywood model to some degree, not to say that building things with plywood would not be good if done correctly.
I would look at it from a what was original cost, vs selling the same two now? Have both lost say 60% of original value? then to me it is a wash. If the oyster lost 50%, and the Jeanneau lost 60% or the other way around, then the one that lost the 60% is NOT the one that is best bought new per say.
Personally I do not feel there is a right or wrong. One has to look at what the boat was designed to do etc. A Jeanneau is not built to the same specs as an oyster, nor were they designed to do the same type of sailing etc, so one would or should expect to see different build qualities and levels. With the way Zan is going thru boats, ie every 2-3 yrs.........buy what your heart desires right now. If on the other hand one is buying for a 5-10 yr run........different answer, go for the better built one if you will! My 02, for what is is worth!
She drives me boat,
I drives me dinghy!