The answer is that revival attempts kept failing. Professional critics are biased wastes of oxygen. They shot down Space Jam (which had enough problems already from mixed fan reaction), which derailed anything beyond the Bugs and Daffy Show for years. Looney Tunes Back In Action had that albatross around its neck when it hit theaters, on top of being underpromoted, and it bombed too, setting things back even more. But now, The Looney Tunes Show has at long last gotten to air. Looks like Warner's board finally realized that maybe just maybe that the way to save their ratings was to revive the characters who were actually funny.