Soldato
I dont believe that the price of a titan has changed graphics card pricing forever as Locky pointed out. I think its more to do with the pound getting absolutely battered over the last decade against the dollar and euro. Paying £500 for a gcard now is pretty much the same as paying £400 for a X1900XT a few years back due to currency devaluation.
The pound compared to where it is now does not equal to the massive price increase since last gen and this gen, AMD set the bar of £500 quid with their 7970 and nvidia have set the bar even higher.