The topic under discussion is whether "AMD is lagging way behind NVIDIA." If some games run better on Nvidia not because AMD is lagging, but because those developers are choosing to make them run better on Nvidia cards, the why is very relevant to the topic at hand. What isn't relevant is which brand of video card you choose to buy.
Even if only on relationships with gaming studios (or game engine builders, which are overlapping but not identical groups), AMD is lagging in a market-critical area for GPUs if games don't run as well on AMD GPUs.
