Workstation Graphic solutions are more expensive is due to the fact:
1) The drivers need to be specially written and tested to be working with most of the certified graphics software, therefore higher cost of development, R&D, product testing, etc. etc.
2) These cards go through more thorough tests in the factory (as compared to consumer mass produced graphic cards).
The drivers in workstation cards are very highly optimized to render accurately, while gaming card drivers are optimized to render as fast as possible. Therefore, doesn't mean that a higher end gaming card will topple a workstation one.
Yes generally 2-D based applications like Photoshop works well with any decent consumer graphic (e.g. GeForce, Radeon series) however for 3-D rendering applications like Maya and AutoCAD where real time rendering is done, a workstation card like the Nvidia Quadro will greatly excel here.