Cleeds,
I respectfully but strongly disagree with your belief that the dealer can or should replace the amp with a new one. As a service manager for high end watches for many years, I can tell you that from the retailer's point of view, once the sale is made, a contract begins between the customer and the manufacturer (warranty).
It is certainly the job of the retailer to facilitate the fulfillment of the warranty in every way possible for the convenience of the customer, but for the customer to expect a brand new piece is not reasonable, unless of course the warranty makes such a promise which in most cases they don't.
You mention B stock. That happens more in the case of manufacturers or large retailers than small high end dealerships, because if they replaced everything that had a small repairable issue with a new piece, they would go out of business.
I had to kindly explain this to watch customers many times.
Of course, due to the realities of the business world, there are very rare occasions where a very good customer who has spent a lot of money in a store will be given a more-than- reasonable accommodation to keep them happy and not lose their future business.
It is very unfortunate that these warranty repairs sometimes take so long to perform, keeping the customer waiting for months.
I also disagree with your belief that only those who ask get new replacements. When it comes to expensive gear, asking is usually not going to get you what you want in most cases, but from one who was also a retail manager at Macy's for years, I will say that if you have a big mouth, and aren't afraid to shout in front of others, you will usually get that undeserved discount or expired coupon. Retailers like to avoid scenes if the monetary loss is negligible.