But do you think Star Trek ever got on TV if this horrible fightscene was the pilot to sell it?
I don't think Star Trek is popular thanks to this scene.
They 'got away with it' because they were already popular.
I think it's also a bad idea to compare shows from a totally different era to stuff you're producing now. When Star Trek aired the average viewer had a dozen channels or less to chose from, no home videos to watch, and no internet. It wasn't even a particularly successful show for it's time - that's why it was canceled after three seasons. But it's ratings, considered disappointing at the time, put it on par with American Idol because the audience is so fragmented now.
Audiences are more sophisticated now, have far more options to choose from to spend their free time watching, but have no more free time to spend than they ever did. You're competing against a much bigger pool of entertainment options. Your work needs to have something that makes it stand out to an audience amongst all the other choices they have.
And there's a difference between something like Star Trek and the Black Scorpion show you posted. Star Trek was low budget, and slightly campy, but that was largely because it was a product of it's time and not necessarily a deliberate thing. For a lot of fans that's a big part of it's appeal, it has an aspect of nostalgia to it that is rooted in the innocence and sincerity of a time when that fight scene was cool. Black Scorpion is clearly the opposite - the writers/producers are very aware that what they are making is low budget and campy, so they've chosen to up the camp factor quite a bit so the audience is laughing along with the show's creators rather than laughing at how bad the show is. If you're going to have bad effects, bad fight scenes, bad acting, etc like one of these shows I think that's the approach you have to take - you need to let the audience know (or at least think) that those are deliberate choices, rather than shortcomings, because audiences are much more sophisticated than they were 50 years ago.
Also, things have changed dramatically in just the last decade and even when Black Scorpion aired there were a lot less entertainment choices it had to compete with. There was no YouTube, no Netflix, most old tv shows weren't available on DVD, and most people still had analog cable with far less channels to choose from and no VOD. The fact that it's no longer available on DVD now shows that there's not enough demand for the show to justify spending time or money trying to sell it to an audience - which seems like it makes it a bad choice to emulate for your own projects if you're hoping to make them successful.
I'm on science fictions boards for writers and filmmakers. When I asked how many people are still fans of Star Trek, Space 1999, Babylon 5, and Battlestar Galactica, you may be surprised how many people are looking for something to fill that void.
What void? If you're a fan of those shows you can watch them just about any time you want, as many times as you want, as much as your schedule will allow. There's also been a resurgence of real quality tv shows being produced over the past decade, so there's plenty of new stuff to choose from in addition to watching your favorite old shows. There's no void people are looking to fill - quite the opposite now in fact, the hard part for a lot of people is trying to find enough time to watch everything they'd like to watch. So if you don't have something really unique which will make someone decide not to spend their time watching old favorites you're going to have a hard time finding an audience.