I am generally the type of guy who thinks "because it's a TV show" is a reasonable and complete explanation for unexplainable elements in fictional works. However, given the tendency for Star Trek fans to find intricate explanations for anything that appears on-screen, I'm curious to know if this has been addressed:
Is there an in-universe explanation (or even just an in-universe acknowledgement) of the fact that the various eras of the Star Trek universe parallel the decades of their production in fashion and design? Put another way, why does the Kirk era look so much like the 1960's and 1970's, while the Picard era looks so much like the 1990's? Color palettes, hair styles, fashion design, technological layouts, all conform quite recognizably to the those of the latter half of the 20th century.
Now, obviously the real answer is "because it's a TV show made during that decade," and there is a tradition in the Star Trek universe of cultures randomly developing cultural similarities that may apply, but has anyone ever acknowledged or tried to explain in-universe why different centuries of the Federation seem to echo different decades of prior Earth history?