I can't agree with the second half of your post. Indiana Jones started reasonably strong with Raiders and has been on a steep descent ever since. The secondary characters in Temple of Doom were truly annoying and the franchise only got worse from there. I could be coaxed into watching the first again, but none of the sequels.
And the state of modern blockbusters shows that mass audiences haven't developed more sophisticated taste, they still gobble up slop like Marvel for a dozen+ sequels/spinoffs with thunderous enthusiasm until they eventually, finally, get bored of the premise and start looking for some new slop. MCU isn't failing because audiences got more sophisticated between five years ago and now; it's failing because they've been putting out the same movie with reskined costumes for 15 years now and that was never going to keep people interested forever. It still had one hell of a run though, proving that audiences today don't have more taste than audiences in the 80s.
And the state of modern blockbusters shows that mass audiences haven't developed more sophisticated taste, they still gobble up slop like Marvel for a dozen+ sequels/spinoffs with thunderous enthusiasm until they eventually, finally, get bored of the premise and start looking for some new slop. MCU isn't failing because audiences got more sophisticated between five years ago and now; it's failing because they've been putting out the same movie with reskined costumes for 15 years now and that was never going to keep people interested forever. It still had one hell of a run though, proving that audiences today don't have more taste than audiences in the 80s.