The difference is in Walt's day (and for decades after) theme park structures that were supposed to be old were built of the actual, traditional, authentic materials (e.g., wood, brick). In recent decades WDI has moved away from using natural materials and methods to using long-lasting, weatherproof faux-materials (e.g., sculpted concrete or pvc). So newer areas that feature "wooden" buildings, signs, roofs and fences - HKDL & Shanghai in particular - tend to have a waxy, overly-smooth, artificial feel and don't get Nature's patina, regardless as to whether they are intended to be well-maintained (DL Haunted Mansion) or dilapidated (Paris' Phantom Manor) (both of which were built the old way out of natural materials, not so for Mystic Manor).
The easy analogy is comparing a historic house with natural cedar siding or the same building with vinyl/pvc siding, even the type that is manufactured to look natural. It never quite does.
*** Here's a pic MK's Fantasyland under construction with a natural cedar wood roof. Far cry from the colorful, geometrically-perfect, plasti-'wood' roofs that replaced them:
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