Actually
@4K8KW10 is right. TSMC maximum size for a 7nm chip is 429mm2. RTX2080Ti shrank to that node is over 520mm2.
Except if Nvidia starts chopping parts like all RT or Tensor cores, is physically impossible to have the GPU of that size manufactured. Hence the true meaning of his comment, sarcastically mocking that Nvidia cannot make a 7nm chip from Turing and has to give up something.
Many expect that Nvidia will stick to 12nm for 2020.
And is all about yield. The bigger the chip the higher the failure also, so higher the cost.
Even AMD with it's 74mm2 Zen2 will have yield issues on 5nm process, except if each chipplet becomes quad core.
Consider Nvidia trying to squeeze the 752mm2 12nm behemoth to sub 100mm2 which has 30% yield.