Partially what Maelstrom said, and partially because while Marzocchi may begin entering the rear shock market, Manitou, Fox, Avalance, Progressive, and Romic have already taken most of the market.
The Vanilla RC is now the "low tech" shock on the market. Marzocchi is a day late and a dollar short with this shock. It won't be anything special, and knowing Marz, it'll cost more than a Romic.