Oh, I don't know. I think a good argument could be made that following Star TreK: Enterprise, people got pretty tired of Star Trek and 700+ hours constituted a "glut." There was so much Trek out there that Paramoun t/CBS couldn't generate any more interest in their property. I could esily imagine the same thing happening if dozens or scores of fan productions are out there, making even more Star Trek noise that people just tune out.
There's a point where we complement real Trek and a point where we simply sabotage and water down the brand. I don't know that anyone really knows where that dividng line is--and it's probably a moving target anyway.
I hear what you're saying, and you might very well be right, but ...
Where is the glut of crime dramas? Medical dramas? There are so many of each on the air at the same time, you'd expect them to have run their course by now. And yet, they continue to draw strong audiences despite a lack of amazing effects and different settings. They're always set on modern day Earth ... usually in someplace like Los Angeles, even!
The only thing that varies are the characters, sets, and style and quality of the writing, and I'd argue that those same qualities can lend themselves well to diversity within amateur and semi-pro Trek productions. And how often do these productions put out new episodes? A few each year at best? That isn't causing any kind of a glut.
Oh, and Dennis and NEO f/x: that's damned exciting news. I'll take this opportunity to remind you again that I've held off from watching anything past the teaser in anticipation of seeing the whole thing in one sitting. And I really want to watch this!