Thank you, Ron, for that very thoughtful, insightful post. You've summed up the eBay dynamic nicely, and accurately.
That said, you can usually find any of these "rare" plants from other sources if you are willing to do a bit of diligent sleuthing; most can be had for significantly less money than "the frenzied few" seem willing to pay. Case in point, I bought my S. 'Adrian Slack' from a well-known private seller for $100, shipping included. And yes, it is the correct plant. At a time when Cephalotus were selling on eBay for hundreds of dollars, I was able to purchase plants with 1.5" tall traps, in 2.5" pots for $25 each, again, from a private seller who produces hundreds of plants. I got on a waiting list for a US grown plant of N. macrophylla months ago, and was able to obtain a 4" diameter plant with 2" pitchers for a very reasonable price; it was all about my willingness to wait. Needless to say, I am on several waiting lists for some of the more desirable plants extant. In some cases I have been waiting for close to a year, and I may wait as much as a year more. I can work with that.
You can certainly find some of the more desirable plants on eBay, but you are unlikely to obtain them for reasonable, rational prices. For that, you need to search further afield and some patience.