I do like in Star Wars how styles tend to get more '70s looking the closer you get to the Galactic Civil War era. It makes it feel like an actual time period.
I think the deeper appeal comes from the simple fact that the 60's just look cool. One thing I have noticed with lots of young people is they have a love for retro. Clothes or tech. It's all the same. A fascination with looks and designs to time periods they never even lived in. When you get right down to we are right now living in the most boring visual era of all-time. Nothing sexy about touch screens Musk cars that look like metal garbage.
People love the convenience of modern tech but not the aesthetics and even then not always the convenience because people can tell we have lost something that feels more naturally human with everything being so easy. That's why Trek embracing more 60's look isn't just a canon issue. It's also a chance to show people something really cool to look at because you make that 60's look come alive with out the shortcomings of just being limited to 60's era level of tech knowledge.