Dave, I don't sense that anyone is arguing with you. The previous posts by members go into great length to assist with information about their boats and experiences. I would not use eBay as a measuring tool for the value of anything. I use eBay alot to buy and sell items and pricing fluctuates significantly there.
On Triumphs retaining their value...I bought a 2003 Triumph 210 with Suzuki 140 4-stroke in September of 2002 and sold it last fall for a little over 10% less than I paid for it. I had some modifications and additions to it but for a 3-year old boat I thought that was pretty good. And the buyer was happy to get it at that price. I hope this is helpful.