As a writer and a member of the human race you must contemplate this question even if you choose to only write warm fuzzy love stories set in the unattended public toilet of the world (New York.) On some level, even your love story must be firmly grounded in the beginning and ending of humanity. When it’s not, it shows. Readers and viewers cannot tell you _what_ is missing just that _something_ is missing. Even the desire to marry and have children is rooted firmly between the murky beginning of humanity and the end procreation attempts to stall off.
Millions of fans, myself included, fell in love with “Babylon 5.” Not that it matters, but I have the entire series on DVD, even “the Lost Episodes.” This show survived despite multiple networks trying to kill it. The fan base was relentless. Other science fiction/fantasy shows, actually far too many, don’t last a season. Most you will never hear about. Why is that?
The short answer is “the writing.” Oh no, I’m not talking about the script, I’m talking about the “cannon fodder.” A good many television and film executives don’t return a phone call or email about a science fiction show not because they don’t sell, (just take a look at Star Trek!) but because they don’t wish to pay for the “required dead weight” or “cannon fodder.” This is the writing which will never really be seen, yet always be directly on the screen. They would much rather pay for a fake reality show which has no back story, current story, or future story. So much cheaper to put on. Today it is all about putting out Walmart quality.
If you go through all of the “bonus features” in the “Babylon 5” DVD’s you eventually encounter a conversation with the show’s creator where he speaks about the groups of people who created complete backgrounds for each alien species. This included the language, predominant religion(s) and most widely known cultural stories. These backgrounds became desk references and required reading for anyone admitted to the team of writers for the actual scripts. There is also a cute comment about all of the “alien writing” appearing in the show was actually profanity written in the languages found in those binders.
Were any of you to bother clicking the earlier links about shows shot out of the saddle quickly I will wager a bit of research would prove they tried to “do it on a budget.” The easiest thing for an executive to slash is the “cannon fodder.” They have no idea what it really is, kind of like that “mystery dealer markup” you encounter when buying a car. There is no direct line one can put on a spreadsheet which says X dollars of “cannon fodder” yields Y viewers. Even worse, there is no line to say W dollars or less spent on “cannon fodder” ensures the show doesn’t last a season. As I said, viewers cannot tell you _what_ is missing just that _something_ is missing.