GP200 likely won't ever exist, we will get GP100 and then will move to Volta with GV100.
Nvidia have to provide a big pascal for compute purposes. I wouldn't read too much into TSMCs roadmap tbh.
He means GP100, generally a big Pascal chip also while TSMC's road map is irrelevant, chip size has little to nothing to do with the process name or capability, if you can make a 75mm^2 chip or a 300mm^2 chip, you can make a 600mm^2 chip. The power/leakage or process name doesn't effect that, only max reticle size does(literally the absolute maximum they can create a mask to get accurate etchings on the chip). Yields are the only difference between realistically being able to make a huge chip and not being able to.
We really don't know what the yields of huge chips are at this point at TSMC or Samsung. Realistically the big chip yields have decreased process on process since 90nm, becoming increasingly difficult at every node.
There is a crossover point where yields are good enough to release a product and before that point while you can make them you might not have a viable product. Even talking about enterprise/professional prices, if you can only get 2 chips per wafer, even if you can charge 10k per chip and make a profit doing it, releasing a product with near zero availability still isn't a realistic idea.
The question with 16/10nm is which comes first, yields on 300mm^2 chips at 10nm or yields of 500+mm^2 16nm chips. Or not quite, if it's predicted today that you can make a 10nm medium sized chip within maybe 3-4 months of a 16nm big chip being doable, it becomes a needless cost to tape out a huge chip on 16nm as a lot of people will just wait for the 10nm chip anyway.
In terms of size, if medium Pascal has the same compute ratio as big Pascal, then there is no need for the bigger one. Presuming it has beefed up compute anyway then a medium chip will beat current compute offerings handily anyway.