Soldato
Standalone Vega 64 at £550 is not aimed at gamers. It is aimed at miners.
That's the only logical explanation I can come up with for this price. AMD cannot afford to sell this for less without making a loss (as Gibbo has suggested) and they know it doesn't compete with the 1080 on either price or power consumption, and only matches its performance. It has no attraction to any sensible consumer who is not tied into Freesync, unless your a miner.
AMD knows this. They knew it would fly off the shelf under current market conditions which is in the midst of a mining craze. It's a good business move.
Like I said before, if you're a gamer, the decision is clear.
Relying on miners to buy a crap card for mining .... it's a .... well it's not any strategy anyone would ever think to do.