I too suspect that the alliance of the airline have something to do with that. However, it still does not really explains why the increase discussion of economy class vs premium class of travel except perhaps the "old" hardware on board.

With regards to the cost involved and value for money, thai is similarly regarded as that for economy travel, but yet the discussion of their premium travel still outweight that of their economy travel. So my feeling is that this might not necessary be the key point.