OK, let me rephrase that. Fares to London, adjusted for inflation, aren't that bad. I remember when I was a grad student at Oxford back in 1977-79 and I would come back to the US between terms and over the summer for $99 each way (back then, there was no such thing as fuel surcharges and taxes/fees were much lower). I'm no economist, but probably, adjusted for inflation, fares today to London aren't much higher than they were in the late seventies.
However, over the past few years, we have indeed seen dead of winter $99 each way fares to London and other European cities (mostly for Mon-Wed non-holiday travel in Jan/Feb). I'm not so sure we'll see that this winter.
I recently flew back from London to New York JFK, and at immigration, where they divide arriving passengers into "US Citizens" and "Other" I'd say 10 percent of my flight went to "US" and the rest to "Other" suggesting that the reason fares have remained so high is that all those euro- and pound-rich foreigners are filling up all the seats.
Which leaves us with rather unexciting seat sales such as this from Virgin Atlantic: $322 round-trip plus tax, which comes out to around $488. And this is for dead of winter Mon-Wed travel. The lowest fares are from Boston, JFK, Newark and Washington and are higher from other Virgin gateways.