I suppose that's true. But I think it's also because when you're a kid, sci-fi was wondrous, bad or good, but I suppose that might lend to your theory of the genre not being well developed. However, there was quite a bit more sci-fi than most people think. Star Wars: A New Hope, Star Trek the Motion Picture, Battlestar Galactica and Buck Rogers all came out in the late 70s to early 80s.
Star Wars isn't really sci-fi though. George Lucas drew on a lot of myths and concepts having nothing to do with sci-fi and was inspired by movies he liked as a child. For example, the starfighter dogfights that took place used movements drawn almost directly from movies about WWI dogfights. You can put them side-by-side and the only change is the replacement of the actual craft. I know you'll probably tell me that it's quite common but I don't believe it was in 1977.
But I digress. There were a lot of lame shows that we watched because we were limited in choice and networks didn't have to compete as much. There are still lots of lame shows but at least better thought-out levels of lameness. Of course, there's still reality tv, which has no comparison to anything back then, other than celebrity news.

As far as Buck Rogers goes, I guess it doesn't matter if I piqued your interest as I can't find any full episodes online, just snippets. I hadn't realized until I did some searches that there was a movie before the TV series. The show was cancelled after only 1 or 2 seasons, unfortunately. Strangely, when it first ran it was tied with Laverne & Sherley and Benson, the most popular other shows (so the Buck Rogers star says), but then after the first few episodes, they decided to stop the series to upgrade special effects and lost their audience because they figured the series was already cancelled.