Thanks for an excellent primer on scriptwriting. Movies & TV are essentially mass entertainment and as such need to be formulaic in order to ensure the average person can instantly understand what is being conveyed. All movies and TV shows must conform to one of a limited range of pre-existing formats (even "brave new mould-breaking" entertainments are simply old cliches with some glitter on top) and it's essential to understand these formats in depth in order to recreate them. Which is why TV and movies are inherently disposable and as long as we understand this, we can have no complaints that these formats never explore matters of importance and are generally forgotten as quickly as they are created.