While technically the same hardware, isn't it the case that the "higher end" products are the units off the production line that met a higher QA bar?
That's my understanding of how it works for CPUs. A four-core CPU with questionable functionality on the 4th core may be sold as a "3 core" CPU. Depending on how "questionable" the 4th was though, it might be possible to use it anyway.
I don't think production quality is the only reason. Sometime it's cheaper to design one product and sell it as multiple products to capture more value. For example, some people are willing to pay 1k for a graphics card while others are only willing to pay 300. So you sell the same graphics card to both groups but for one you artificially lower it's capability. This allows you to capitalize on the market a lot more efficiently than selling your product either at a low price or a high price.
With Tesla cards, you get a professional-oriented driver that is good for Maya and CUDA, but not optimized for games. There are also a few hardware features that are important for pros but are not an issue for gamers --stuff like ECC RAM, double-precision fp, better handling of multiple 3D viewports.
But, it's my understanding that most of what you pay for when you buy a Tesla card is support. If you call Nvidia saying Maya has a driver problem with your Tesla card, they will pay attention. If Maya has a problem running on a GeForce card, they will direct you to the forums.
Especially you have only one product to produce on the highly expensive PCB/chip manufacturing lines - if you experience demand shifts, just reflash the BIOS and change the packaging.
Way cheaper (and more flexible!) than ramping up different production lines.
That's my understanding of how it works for CPUs. A four-core CPU with questionable functionality on the 4th core may be sold as a "3 core" CPU. Depending on how "questionable" the 4th was though, it might be possible to use it anyway.