Your latter observation is not surprising. The 60s-80s were times of confidence in the future, in progress. We visited the moon, flied in supersonic airliners, and we were confident that we would keep exploring always further, always faster.

Now that spirit has largely faded away, the West seems to have lost faith in progress in exploration and is focused in preserving what we already have - sometimes for good reasons (environmentalism and fight against climate change), sometimes not (disproportionate attention to minor threats like terrorism, fear of immigration, etc.)

Musk clearly still believes in progress and exploration, hence it's not surprising that his designs end up evoking reminiscences from that era.