Originally Posted by
i_fly_AA
In addition, if you pay them 50k miles for the Y seat, that means that they can't now sell it to someone who may be willing to pay full fare. So all in all, it's a win-win situation for them to get you to take the 45k F seat instead of the 50k Y seat.
It's also, sadly, now hypothetical since they raised the MileSaaver F award to 50K.
Only AA and UA currently offer the "real thing" last seat-for-sale redemption at similar (ie double) mileage levels. CO only allows it for elites. DL reintroduced it at a yet-higher third pricing level. US does not offer it at all.