And while slow compared to Star Wars, it's pacing was probably not too different from similar movies of the day, such as Close Encounters, so audiences may have been more forgiving and allowed themselves to be wowed by the spectacle.
It's interesting that you mention
Close Encounters, because that's one move to this day I've yet to sit through beginning to end.
Never really watched that movie. I saw bits and pieces when I was younger, but never sat down to actually watch it.
2001 Space Odyssey.... I did try and sit down to watch that back in the late 90's / early 2000's when I was in college. I do believe I watched it through, but my geez.... did it ever drag on. It dragged on so much that after a while I forgot what the plot/point of the movie was, if there even was one.
Hell, that was also during my "Recreational" days and no amount of "Recreational Things" helped me keep interested in that movie. To this very day I still don't know wtf it was all about.
TMP.... well, even that took me a few watch'overs to figure out exactly what the plot was for the movie, but at least I was willing to sit down and try and watch it again a few times.... 2001? I never want to see that movie ever again.
For TMP, I knew there was this big thing coming to destroy Earth and the Enterprise Crew needed to save the day..... and I got the point of it being some old space probe Earth sent out many years before, but everything in between and even the ending went in one ear and right out the other with a big
"Fbbbrrrraapppppapapapapaaaa" sound.
Eventually on the third go through a few years later, I got the whole thing, but during the big Enterprise Reveal and entering V'Ger.... and Spock's travel into V'Ger, I simply just fast forwarded through.
I'm getting all the ST movies on BluRay for Christmas, and will certainly be watching TMP first all the way through to Nemesis..... I'll do my very best to not fast forward, lol.