I think some people don't want the potential attention if it was known that they owned a specific pipe while I think others want to keep their pipes concealed so that only they can enjoy it. I think there's ways around the former. The latter...
Both of those seem distinct probabilities.
I own what is arguably the absolute rarest Barling related item, in my collection, the only complete and intact Pre-War Barling catalog known to exist. It was B. Barlings & Sons own reference catalog, so it also has marginalia regarding pricing, etc, circa 1914, written into it. The former owner was a retired director of Barling.
I didn't buy it with the intent of hiding it so that only I could enjoy it. I bought it to save it and make its contents available to anyone interested. The purchase and conservation wasn't cheap, and the 150 hours of carefully digitally restoring it would have cost a small fortune it I hadn't known a world class restorer, me.
I published it and sold enough copies to break even.
And now, it's out in the world. And you can download it via the Pipedia Barling Page. So don't go buying inferior copies off of the IP thieves on eBay!
The point is that when we share we all benefit