"Science fiction" may continue into the future, no matter how advanced our technology gets. Although I prefer the harder brand of science fiction that sticks closer to physics as we know it, many fans accept time travel, alternate universes and other truly fantastic notions without blinking.
Agreed, but what about within STAR TREK? Stories about warp drive, time travel, alternate universes, transporter beams, etc., would not be that wild to Kirk and Picard, but more like another day at the office.
So there's a whole genre of ours that would be something else to them, the way 20,000 LEAGUES isn't sci-fi to us anymore.