Hmm.. Wikipedia lists the MSRP at $399 for Vega 56, $499 for Vega 64 and $699 for Vega 64 Liquid.
So, we were both wrong ... and it makes even less sense.
$200 price increase for liquid cooling and only a marginal performance improvement ...
But yeah, preorders for the card over here are more in line with $600 for Vega 64 (Air), but no NVidia 1080ti for less than $700.
Maybe the vendor you saw got scared by the AMD hype and reduced the price of the 1080ti prematurely... or do you list a MSRP for comparison?
I see that the Vega 64 does 10.2 Teraflops (single precision) while the GTX 1080 does 8.2 -- but the NVidia cards still beat AMD in most games.
I thought that Vega was supposed to be better optimised for games, and finally use deferred rendering in tiles like NVidia has done for the last two generations to be able to catch up, but no. I'm disappointed.