I was a teen when this was on the air. It made science and related subjects much more approachable and easy to understand without pandering.
Nova, the other science program offered by PBS, was drier and more clinical in its approach. Rarely could I sit through an episode.
The Infinite Voyage had my attention from start to end.
I think the visuals and the audio made a big difference.
Sadly, The Infinite Voyage is a memory now, having been discontinued. A handful of episodes can be found on YouTube thankfully.
As documentaries have changed in the decades since, it is probably a good thing it was discontinued. It set the bar high and few documentary series could reach it. Contemporary documentaries fall far short now.
On a positive note, Nova improved thereafter. I think its producers took cues from The Infinite Voyage and borrowed the visuals and audio cues.