God you love to get screwed by salesmen. Zegna pants for $300, Beautyrest for $2500. Did you even price it out with 1-800-Mattres?(leave off the last "S" for savings!).
As to the longevity, any decent mattress will last you at least 10 years, flip it every 2-3 years. Mine (Stearns and Foster) last a lot less, but I'm a sexual dynamo so that attributes to their demise.
I don't think he got screwed, on a price-basis anyway. I got mine through a senior VP at the company and I paid factory cost, which ended-up being ~$1300. I saw the one I have at the Linen Chest for $3200. The Blacks are considerably more expensive although I think there's no extra value in them. And these beautyrests are no-flip mattresses btw.