As Raymond says, the original leather isn't readily available (actually you can source something very similar if you make a not inconsiderable effort), and the original artisan is usually not the one doing the restored interiors, so the style & characteristics tend to differ quite visibly - if you know what to look for. Another issue is restored cars are often owned by people who insist on the current thick bulky matte-finished leather being used and this in itself creates a difference in the finished appearance which is a departure from the original authentic finish, because the seams are less tight and the stitching has to be bigger to accommodate the thickness of the leather, and the overall patina of the leather is dull. Another mistake is the use if much less padding these days, causing the sitting area of the seats to wrinkle and the leather to become loose after just a bit of use. If I were a concours judge, I'd start in the interior of a restored car.
Long time no see. enjoyed retirement, sort of. Doing my own things now. No more corporate non sense dealing. My question on this leather saga is, being 2024, why could not anyone perfectly replicate the original leather? I mean technology should help. Someone made it to start with.
Discounted prices could also be due to the very aggressive policies toward shutting due gas cars in the EU and pushing EV. Hearing that cities will now forbid driving a gas car in them. These cars will be boat anchors there, never to be driven again