As a young child in the 80s TOS always looked fake and old to me, but the stories were so good that I didn't care all that much. Even as a kid I was smart enough to figure out that a bigger budget and more advances in special effects technology is why the TOS movies from the 1980s looked so different from the 1960s TV show.
Though I suspect whatever really looked fake to audiences in the 1960s would continue to look bad. I remember when the Borg cube was destroyed in TNG's Best of Both Worlds Part II
, it looked really fake to me in 1990. But to someone born around that time or after, they may look at that scene and think it looks dated, when it always looked bad. It never "looked real". Again, it was the story that carried everything.