Quiet the opposite, i expect your average consumer to see a box, retailers page or whatever, see a 1060 3GB and 1060 6GB and assume the only difference between the two is the amount of RAM, i expect your average consumer doesn't have a clue what a CUDA core, streaming multiprocessors, or texture mapping unit is, that's even if a retailer listed those things on the product page or box.
Isn't that the point, the consumer knows, or even assumes, that both 1060's would be identical other than the amount of RAM, it seems a bit like buying a Golf only to find out it's a Polo in disguise.
IMO that's the problem though, it's not going to be slower *just* because of the RAM, it's going to be slower because one of these GPU's isn't like the other.
And that's what i have the problem with, marketing wise your average consumer is likely to assume the technical details, the type of GPU (type as in what the consumer considers a type) is the same from one 1060 GPU to another.