As for the BYOB option, how would it get chilled? As far as I know, Duty Free doesn't generally sell cold bottles, and even if they did, it would warm up quickly if you just keep it at the seat...

Back when I used to fly WT (or its equivalent on other carriers) it was easy for me to bring a bottle (generally something nice and red, so that the temperature wasn't such an issue) from home in my hand baggage (together with any manner of snacks that I wouldn't get through security any more). For the record, the wine often served as a nice conversation starter, whilst the pungent French cheeses were often a way to get the whole row to myself.