Have you seen background line in any book published after the 3 cores ? Do you think if there was no background lines in the Psionics Handbook, the Monster Compendium (Monsters of Faerûn), the Manual of the Planes, Deities & Demigods, Monster Manual 2, Oriental Adventure, Book of Vile Darkness, Forgotten Realms Campaign Setting, Tome & Blood and other splatbooks, etc., it was only as a gimmick to differentiate them from core rulebooks and not because complaining about these rules started on Day 1 of availability of the PH ?