Totally agree thay modern movies have gotten away from a meaningful original soundtrack. Most movies seem to use music that is already popular, meaning they take songs already created and use them as a premade sound track.
i think, however, you have glossed over a very very important composer in john williams. Williams has composed some of the most incredible and memorable sound tracks in all of movie history. He is unquestionably the greatest composer in movie history and you cant tell the modern history of hollywood without talking about him. In other words, you cant talk about modern movie sound tracks and dissmiss the best and most prolific sound track composer.