Science fiction stories are mostly the ones that end up infected by this sort of plots, which not only lead to silly, unpleasant pieces of work but, worst of all, they also offend human intelligence. And that is the main problem. These kinda magic plots I am speaking about allow the scriptwriter to freely make up whatever story he likes in order to get his hero out of trouble: all of a sudden he may be given the utmost power as to being immune to bullet wounds, or maybe he can have either the gift of outright immortality or the ability to fly back to the past to fix a problem.
Storylines where anything goes totally invalidate everything which has previously been argued for. The interesting thing about the universe is that it obeys rules. On the contrary, a magic universe -that is to say, where there are no rules- arouses nobody's interest. But when the universe imposes constraints, then that superhero is forced to deal with that difficult evil if he wants to save the princess. So... if there had always been a chance for him to be successful at the touch of a magic button in the last act... why not clicking it at the very beginning so as to keep us safe from getting distressed? Maybe he was acting dumb?
Nevertheless, there is still a glimmer of hope for fiction literature of quality. In fact there are outstanding contemporary writers of both science and fantasy fiction stories where magic is common. But this kind of authors have no need to either deceive or get their readers all muddled up by using the old trick of rewriting new rules to make the plot work.
Yet I should not be surprised by certain novels' success... The book which offends human intelligence the most is none other than the one most sold in the entire history of mankind.