Prices for Xmas and after are pretty high (in comparison to their usual lows)... my SFO-IAD trip around Xmas was $579 per person. I'm lucky I had a bunch of vouchers to use or I wouldn't have been able to afford our tickets. (And yes, I realize that even at $579 it's still cheaper on an inflation-adjusted basis than it was even 5 or 10 years ago.) For comparison, a nearly identical trip last year was under $400.

With regards to the value of 15K RDM... I don't know if I'd value them at $.01, $.03, or some other value, but I can say that I much prefer to spend my miles on award travel rather than upgrades. I pay for travel, but I don't pay for upgrades, so spending my miles on travel saves me real money, while spending my miles on upgrades would get me a better experience but save me nothing (and, next year, would cost me $50 each time). I'm willing to forego the extra niceties of F if it means not having to pay for my next trip.

That said, if I were to fly on a Y/B fare (say, if flying on a Y gov't fare, which is bound to happen at some point), I'd probably cough up the 5K RDM that it will cost as of next year for the upgrade... that's a value I can get behind.