Bit of a tricky one that, But the usual pecking order as you know with Nvidia is to release a top of the line card such as the GTX 1080. And then follow it up with a GTX 1080 Ti version with more graphics horse power.
I would think Nvidia would want to get there money`s worth out of selling the two cards for at least the next few months.
Before even giving Joe public the Volta range of GTX gpu cards first Ambam.
When it says 2017, it will most likely be positioned at the end of 2017. Slotted in for release just before Xmas.
Would be the most ideal time to launch the new Volta based cards.
For the holiday season.