I'm in my thirties. Many other sci-fi fans are also, and older. There is a generation of young sci-fi fans who have not read or viewed what we have read.
I was reminded of this while watching another Stargate: SG1 episode where the team is thrust back in time. Immediately following their "arrest", they are seen sitting around a table discussing the issues that involve changing past events to prevent future atrocities.
This is very old science theory for many of us. I found myself sighing and wondering why the writers bothered. That's when it dawned on me that not every episode of every sci-fi story is for the veteran fans. Sometimes the writers and producers have to keep the novice members of the community in mind. They don't even have to be young viewers, just people who haven't bothered to keep up with science or sci-fi.
It's an important step towards information the younger generations. A step that seems to be frowned upon more than it should. On the other hand, let's not fall back on this style of story-telling just because we can't think of anything else to say.