I think nvidia really got theirself into a situation here with the GK110 cards. I believe they intended Titan to be a halo product and use to sell of unused Tesla chips. When they figured out TSMCs 20nm tech would be (yet again) delayed, they took the bullet and released an "entire series" of GK110 cards. It's probably even the same reasoning for AMD.
Of course now both companies have to a)wait before 20 nm finally materializes and b)their top-cards will be in an awful position to compete with the big chip GK110/Hawaii. If rumors are true and 20 nm will actually not bring much on the table, I could see both AMD and Nvidia in a position where they either have to release big chips from the get go or they might not even see a performance increase at all. I mean you never know if your planned architecture is actually better (see Ivybridge/Haswell).
Of course now both companies have to a)wait before 20 nm finally materializes and b)their top-cards will be in an awful position to compete with the big chip GK110/Hawaii. If rumors are true and 20 nm will actually not bring much on the table, I could see both AMD and Nvidia in a position where they either have to release big chips from the get go or they might not even see a performance increase at all. I mean you never know if your planned architecture is actually better (see Ivybridge/Haswell).