Spending £300 on a graphics card right now will get you something which absolutely destroys a PS4, and you could buy it over 6 months ago (670).
Anything above a 660 (best price : performance nvidia gaming card), you are paying a huge premium to get something which is only like 10-20% better.
For a single 60Hz monitor at 1080p (comparable to next gen consoles), a 660 will max most PC games that are out there. For £160-180, that ain't bad.
£500 cards are for ultra HD monitors, multi monitor setups, 120Hz monitors or 3-D setups. Consoles can't even compare with that tech, this gen or next.
I really don't see how PC gaming is "dead".
And yeah, spending £500 on a graphics card is massive overkill, don't expect to get value for money, expect to get some of the fastest tech available right now (besides £1k Titans etc.)
99.9% of PC gamers won't need more than a 660 to enjoy their fav. games on high-max settings on a single 60Hz, 1080p monitor imo.
We have no idea how much it costs nvidia to produce this kind of technology, but I bet it isn't cheap, and they need to make a profit at the end of the day. If you really don't like their pricing, there is always AMD