There is a lot of financial turmoil in the USA, which is where most Vipers are.
Families are faced with a choice of foreclosure, health crisis, college tuition (student loan agencies arent lending anymore) and possible job loss.
This is a change from the boom years when Vipers were bought in an age of prosperity.
Pulling the trigger on selling a Viper means opening up an injection of Cash, and also ceasing the ongoing costs of insuring, repair, etc.
Gets a bit crowded on sales side if everyone does this at once, since buyer's market is small, making prices fall despite the US currency being worth less but the Viper being the same fixed item in replacement material, while currency moves.
When stocks are so low, blue chips become accidental high-yielding dividends, meaning if one was considering selling Viper anyway in few years, could sell Viper cheaper than book value now, invest, and end up with more than the book value in cash next year.
If one wants to make money, there are better ways than a Viper. If get happiness from a kick-ass car though, then among ways to purchase a car for around $30,000, then dollar-for-dollar, a Viper is the best value around today, for both price stability and possibility of appreciation.