Understanding the Workstation Market:
The first thing we need to talk about is the difference between workstation and consumer GPUs. The GPUs themselves are essentially identical -- NVIDIA's Quadro K6000 is based on GK104 (Kepler) the older Quadro 6000 is a GF100 (Fermi)-based chip, the W9000 uses the same GCN core that powers the HD 7970/R9 280X, and today's W9100 is essentially identical to the Hawaii XT core inside the R9 290X. What sets these workstation cards aside are the amount of RAM they carry (typically 2-3x as much as a consumer card), their validation cycles (workstation GPU cores are hammered on far more than the consumer equivalents) and the amount of backend vendor support and optimization that AMD and NVIDIA both perform.
This optimization process and long-term vendor partnership is what distinguishes the workstation market from the consumer space and the need to pay for some of those development costs is part of why workstation cards tend to cost so much more than their consumer equivalents.