Old literary, stage and film tropes that always bugged me included "the heroine gets abducted and put into a harem and the hero has to save her" and "hero/heroine falls in love with person of different race, who is revealed to be European." What was the reason for these?
Tropes are arbitrary categorization of storylines by people who have nothing better to do. Any meaning to the trope is solely due to an agenda of the person describing the trope. THERE IS NOTHING UNIVERSAL OR PROFOUND ABOUT TROPES!
Sigh. I am saying to ignore tropes. The only meaning to a trope is that imposed by the person who declares the existence of such a trope. He or she has defined the shape of the box into which the stories have been stuffed. A trope is not a template used to develop a story. A trope is a pattern perceived by someone, after the fact, to group stories together. Often a trope is declared to dismiss stories as trivial or formulaic. You lose absolutely nothing by turning your back on tropes entirely.
Interesting question. It depends, really, on your frame of reference/perspective, I think, and on the view you take of "reasons for literary things" in general. Christopher Booker has very interesting views of these and other tropes, discussed in his book "The Seven Basic Plots: Why We Tell Stories". It's a strongly Jungian interpretation of them, though. But very interesting if that isn't going to put you off, and you're open to an interpretation showing how profound and significant such tropes are, not only in literature but also to culture and society. LOL - please excuse the observation that this is the only forum I've ever seen in which it seems to be quite so tiresome and unwelcome to the staff if the members wish to have conversations that don't interest them - it makes you wonder for whose benefit forums exist!