Sure, but a lot of the retail cost of the card is determined by markup. If VisionTek wants to go for lower margin/higher volume, the more power to them.
Remember, until very recently SDRAM was being sold below cost to consumers across the board. It wasn't inferior product, it was a competitive marketplace that drove the prices down.
I wouldn't be worried about Geforce3-class cards (or better) from 3rd party manufacturers. Maybe I've been living in a bubble or something, but I haven't heard any real complaints about 2D image quality on a GF3, from any manufacturer. And Visiontek I regard as especially safe -- aren't they the #1 graphics card retailer (as of last year) and don't they supply a heck of a lot of hardware sites with review boards? If they had problems with IQ, we'd have heard by now.
I can't find a link to this any more, can someone help me out? Doesn't nVidia require board makers buy nVidia's ram as well as their graphics chips? I remember some hubub about that in the late GF2 days. Does nVidia use any other heavy-handed tactics to standardize their boards?