Never flown other than Economy Class, I think that we should "comsume" what we paid for (no stealing!!) EXCEPT the provider wish to provide you something more (bonus?!). Just like...

FTer's should somehow get their upgrades after the "deadline" the airline can sell the F/J seat. (Think about that, for some restaurants near their close time, they will give you a bigger portion or more dishes than you paid for, my mum is a "big" customrer of a veg. food store so even at the morning she get "special treatment" with extras...

Sometimes airline(same as store) should "buy" their customer's loyality and they will be rewarded eventually.

Seems Asian store having this approach but why Asian airlines don't ? :O