One anomaly I experienced recently is that the Head-Fi guys tend to ask for a good deal more than 50% of original list for used equipment. Strange
This is true. But it doesn't really imply that head-fiers make more money when selling their gear. I think it's a convention in their own little market that allows them to maintain the ridiculous rate at which they all go through gear.
When amp designer X announces a new design is forthcoming, fifty head-fiers step up and pre-order the units at full price. Eighteen months later, when the first units become available, these first fifty guys get their amps. They promptly sell them two weeks later for 90% of the full price. Then the next cohort of head-fiers, the ones who snuffled up those 50 amps as soon as they hit the used market, sell the amps themselves after another two weeks, this time for 80% of the full price. This continues, until the full price of each amp has been shared amongst as many people as possible, and the amp is sitting on a shelf collecting dust (since, by then, 27 new amp designs have hit the market).
This only-slightly-exaggerated description of the head-fi market highlights something important. The single largest determinant of the price a person is willing to pay for a durable item such as an audio component is its expected resale value. Perhaps you think an item is widely perceived as high quality, or maybe there are bragging rights associated with owning a particular brand, or maybe the manufacturer provides excellent support for owners, or maybe the brand is so well known that the sheer number of potential buyers is overwhelming, or maybe you're operating in a market like the head-fiers where convention dictates relatively high resale values. In any of these situations you'd expect high resale values of the item, and would be inclined to pay a high price.
To answer the original question, then...
If buyers were prepared to pay a 25% premium (for example) for a component produced by a large company when purchased new, there is no
a priori reason to think the consumer will not be prepared to pay a 25% premium for the same component when purchased used. Obviously, there are all sorts of things that could well change the relative valuations of two similar components though. For example, if some of the premium was paid for more convenient or superior service under warranty, this portion of the premium would disappear once the warranty expired. If a small, direct marketing firm began to gain wider acknowledgment for the quality of their work, then the premium paid for the large company's product would shrink. If the large company shows signs of financial distress, and people worry about their ability to provide ongoing product support, the premium paid for their products would shrink. These statements are just as true for used products as for new.
Chad