If you assert that none of this is real, why does it matter whether it looks "dated" to us in a fiction?
All of this is set hundreds of years in the future. Who knows what kind and how many different aesthetic changes and fashion trends will occur between now and then. Whose to say that in the mid 23rd century, fashion and architecture will have similarities to the 1960s and styles in the the late 24th century might have similarities to styles that were popular in the 1990s?
There's no reason why the TOS look or TNG's is any more or less believable than SNW. Over a twenty year period, three different Trek series (TNG, DS9, and ENT) had no problem using the original Constitution Class design to tell a story 30+ years after TOS.
I understand they wanted to make some changes for a modern TV series production, and I don't believe everything has to look exactly the same. But the idea you have to visually retcon things in a legacy science-fiction property for it to be believable to a modern audience is one of those things I wish people would stop with, since there's nothing to back that idea up. We just had audiences and fans in this community going crazy seeing the Enterprise-D bridge again, recreated in all of its mid-1990s glory. And it makes no difference in a show like
Andor that everything about Imperial technology is preserved to what George Lucas thought looked high-tech in the 1970s, with monitors that are black and white screens.
Per stories written about the design process that went into the "Discoprise," John Eaves approached the redesign with the point of view that this will eventually become Kirk's TOS Enterprise.
From
TrekMovie.com:
Eaves began the process by producing a series of ten sketches to illustrate how the classic ship could be altered. Eaves wanted to streamline the Enterprise to give it the sleek, Discovery look, yet keep the form as close to the original. As the team was aware that the Enterprise they were designing for Discovery—set in 2256—would be the same commanded by Captain James T. Kirk in The Original Series. They theorized ways their version could be refitted over the years to become the 2266 Enterprise. Their theory was that various components of the ship, such as the warp nacelles and impulse engines, would be swapped out over time, so the team set out to design primitive versions of them.