Having been multiple times at the Chirac Quai Branly museums, it's pretty clear the argument is valid: most pieces seem totally forgettable and would likely have been discarded by their owners. Heck, even the "royal door of XXX king palace" is a 1-meter wooden door with carvings that aren't particularly fine. Those artifacts still exist and have value because they are exposed in a museum in Paris, otherwise nobody would care.
The Netherlands has accumulated so much art and antiques in the last 200 years that most of it never sees the light of day. It sits in giant secured vaults.
> Heck, even the "royal door of XXX king palace" is a 1-meter wooden door with carvings that aren't particularly fine
Perhaps your subjective standards are not universal when determining cultural/aesthetic significance of artifacts.
I saw a railroad spike in an American museum once, it wasn't decorative, or made of precious metal (just steel), but it meant something to the locals. I don't doubt the other adjacent pegs were scrapped or rusted away, but that peg was culturally significant due to the historical nature of the railroad itself.