There's bound to be some economic reason for what we have now. Maybe it has to do with how many content outlets there are.

We can also go online and find older series these days. Tubi has stuff for free, and so does YouTube in some cases.

When I think sci-fi, I think Twilight Zone, Outer Limits, One Step Beyond, Inner Sanctum, and lately Black Mirror. Is that the kind of thing you like, or are you more thinking of Star Trek and similar?