I think it may be because current science fulfills like 20% of what science fiction hoped for 30 years ago. It's like how they're still making crime thrillers set in the modern day that ignore things like unregulated wiretapping, cell phone triangulation, gunshot sensors, facial recognition software in cameras, and post-9/11 terrorism response.
I watched a movie the other day where the most wanted guy ever was driving a super duper car at night with his lights off at like 200 mph and he didn't run into anything or run off the road. The police, though they knew his route across the country and knew what he was driving, were unable to set up sensible roadblocks that would require slow weaving through concrete barriers. They couldn't even get a damn garbage truck to block a road. Of course calling in the military or national guard was not even mentioned. And the SWAT helicopters didn't have infrared cameras which would let them spot him instantly and all his cronies coming up in impractical vehicles. And despite armoring such a car being impossible because it would weigh it down too much, the car was immune to small arms fire. It was a damn stupid movie you could enjoy only if you stopped thinking completely, and any appeal to reality would stop the villain instantly.
What I'm saying is the movie wanted to tell a story and in order for that story to happen it needed to ignore science and equipment that we have now. For a sci fi story to work they need to understand what the scientists are trying to say their science means and what are some possible results. How are you going to get audience buy-in for sci fi when you can't write a story with science? Instead all we get is Star Trek style handwaving. Take Firefly: did they use bullets? Sure looked like it. Sometimes. Did the show take place in a galaxy or a single solar system? Seemed to change between the series and the movie. Was food a valuable and rare thing? When the story called for it.