Sometimes it just goes in cycles. Lots of factors, the economy, area, number of things on the market like it, how desperate buyers or sellers are, etc. The problem to some extent is that there is also now an SE version. Not that the 150 can't be upgraded to the SE version (what's it $2k?). So in essence per many people, you're asking $5.8k for an $8.5k amp that they will have to ship off for an upgrade and incur additional costs and inconvenience. So $6k might be seen as high to some. It's not uncommon when there is a new model or a discontinued model that the value is perceived as less.