Well speaking as a pax who has travelled economy or premium economy only and who always orders the low salt meal (I don't use salt at home and I don't use it when abroad on GP advice) ....my meal has always been served first along with the other "special" meals. That has applied to flights with Iberia, BA, Emirates, KLM, Air France, TUI, Virgin Charter and Cathay Pacific since 2005. Previous flights with Britannia, Court Line, Orion, Thomsons, BEA, BOAC and Thomas Cook many, many, many moons ago did have "special" meals but nowhere near the choice or quality of nowadays and they too were generally handed out before the "normal" meals.