And you are wrong when you imply that the gpu temperature has no effect on the other components on board, the heat WILL transfer on to the other components, whether it be heat transferred by airflow, or heat transferred by PCB. (The PCB is actually pretty good at transferring heat, try to put your hand on the back side of your video card, and you'll see what I mean. There is no magic to be pulled off here, things will get hot)
But then I didn't say it has no effect. Why do you have to pretend I say something different from what I do all the time? I could just as well say that by your logic, if the GPU temperature is 90C then the temperature of the entire room the computer sits in will also be 90C.
I'm sorry if I gave you that impression. I didn't mean it that way.
These are heat measured by infrared, should be good enough to illustrate my point.
This nvidiacard has VRM overloaded at +110C, and its surroundings are +90C.
The core on the right is measured to 84C, but its surrounding pcb area also goes +90C.
And to the far left of both cores you can see a brown spot, that's heat that most likely came from air flow. And of course the motherboard, it takes a lot of heat from the video card too, maybe not so much in this picture(only orange), but in the website I linked to is another image, the motherboard takes up a significant amount of heat(brown).
We shouldn't underestimate the heat that the PCB and air flow can transfer.