Interesting comments on this thread!
I think that expectations are usually driven by experience (assuming there is some!). If there isn't it will be formed by advertising and other media mostly generated by the carrier. So there's lots of room there for disappointment in providing accurate infortmation!
Fortunately, having retired and stopped flying very regularly, both long and short haul, I have little very recent experience on which to base a view.
However, for the last five years all my long-hauls have been Air NZ to Auckland and onwards, usually via HK. Given my retired status I book steerage and occasionally upgrade. Expectations of sustinence are something before sleep and something after! This is always fulfilled almost always with a choice (sometimes at the back and therefore served last no choice, but if you make a fuss they can always find something from premium or Business!)
Given that a flight from LHR to AUK- is just £341 - 2 sectors each of about 12 hours I reckon that any edible food and wine is brilliant. How DO they do that? (Return to CHC is £681 with Govt taxes etc at £468, so the AUK fare is even less than half that as there's the AUK CHC return to consider!)
As in everything in life - you get what you pay for! Pay more or accept it!
And by the way, Air NZ runs the best upgrade system I know. When you buy a ticket you can "bid" a price for a one class upgrade. You may or may not get it, but when bidding there's a "clock" which tells you whether your bid is strong or weak. A friend of mine booked Econ to HK and upgraded to Premium for £200 - vastly cheaper than the listed price and real value.