Leaving aside the fact that a good director and movie studio would hardly put all its money shots in the trailer, commercial aircraft and trains typically have operational lives of some 40 years or so. It's not beyond the realms of possibility that, in the future, a further 10-20 years could be eked out. (The Isle of Wight is still using trains passed down from the London Underground. They date right back to 1938!)
Boeing are still making 747s - though possibly not for much longer given the poor sales of late. They are using different materials, and the interior fit-out has changed over the years too, but it's still recognisably the same base design today as it was when the first one flew in 1969.
There's also the small matter of technological plateauing. Look at the smartphone industry today: it's all just variations on a rectangular glass slab. You'd be hard pressed to tell them apart from the front. Even automobiles now all look very similar. Also, the latest and greatest technology isn't always the best: The Allies didn't have the best tanks in WW2, the Germans did, but they were also much more expensive to produce.
Short of some major new technological breakthrough occurring, I wouldn't expect a galactic empire to be all that fussed about cranking out loads of the same old same old, as long as it works. If the production is automated, even better. It means you can crank out loads of them while saving up your money for that big shiny new toy you have your R&D people have been dangling before your covetous eyes, while being very careful to avoid any mention of its design flaws and many health and safety issues. After all, those can be ironed out later in the Mk. II version.
It's possible I may be overthinking this.
Biting the hand that feeds IT
