... No-one thinks twice about expecting writers to write consistent and internally coherent stuff for shows like Law & Order or ER, and just because their 'canon' isn't about spaceships and aliens doesn't make it any different a concern.
Star Trek should be able to be creative and original, and maintain the consistency of the existing canon. Both. If the writers can't do this, get better writers.
That is quite a ridiculas comparison. Law and Order or ER does not have 28 combined seasons plus movies plus animited series to track. These shows don't span centuries and they did not start off with a vision of future technology that already looks dated. Even if they did, would fans of those shows worry more about the canon of technology than the quality of the stories?
But who knows, maybe the writers do it on purpose. All the distraction over canon may take the pressure away from delivering good plot and sub-plot.
And this is exactly my point - it's always 'canon
or good stories'.
It should be both.
And any long running show is an example of a TV canon in which writers must set their stories. Try thinking of it not as the dreaded word 'canon' but in terms of 'setting'. The writers of a TV show create a universe within the show for the stories to be set in. For a show like
Law & Order or
ER, this universe, by and large, begins from modern day reality, and builds history and characters on top of that.
Star Trek does the same thing, it just starts from a fantastical premise right away. The stories take place within this established show 'world'. Just as a working phaser isn't going to show up in
ER, because that's absurd in the world in which it's set and would break apart suspension of disbelief, violations of
Star Trek's established world are just as absurd.
The setting of a story, any story, not just on TV, is important, and keeping it consistent and coherent a skill. A writer who feels they must mess about with the setting to tell his story is thus lacking this skill - telling stories set in this world is their job.
Just as a cop or hospital show must bow to the realities of the world in which they're set,
Star Trek must bow to the fictional 'realities' of the world in which
it's set. If I work as a staff writer on
ER and want to tell a story about a genuine vampire invasion, tough shit. In this universe, vampires don't exist. If I work for
Star Trek, and I want to tell a story in which (say) the Romulans have cloaking technology decades before they should, the response is or
should be the same: tough shit. In this universe, that didn't happen.