I think it can be summed up in one sentance: You don't throw something out just because it's old.
For example- many of the design principles in aircraft from WWII and even before are still used heavily today, despite the advent of much much fasterand higher flying jets. New technology is generally expensive due mostly to the R&D costs, and often times a newer, better technology isn't worth the extra money, at least not on a large scale. Computers are an excellent example of this. I tend to be more on the Mac side, but generally PCs fit in to this pertty well. I'f I were to buy a computer before the introduction of the first pentuim or PowerPC processors, I would have some usefulness, but once those two lines were revealed, computing power reached a revolutionary new level. Unless you want to run the most advanced software in the most intensive tasks, the older computers dating back as far as say, 1996 will do just fine. This shows on ebay, where computers that old are selling cheaply, but also quickly. In fact, except for the now widespread use of USB over older serial and parellel type of devices, these older computers are just as useful as the day they rolled off the line.
On a more personal note, I am only buying a new computer because I want to switch back to Mac and also run a new flight sim that requires a much more top of the line processor, otherwise I would plod along with my current, much older systems.
I'm sure the same would prove true in this situation. Most of the ships and systems would most likely go along as they were for years and years, due to the lack of corrosion, decay etc in space. Not to mention, sometimes something that works well is produced for a long time, like my old cutlass supreme. between the mid seventies and the 1989 the oldmobile cutlass supreme line stayed for the most part the same, only changing in minor additions or revisions, and was only changed after Oldsmobile realized these old cars weren't dying, they were too reliable, so they needed to be replaced by something flashier and less reliable at the end of the 80's.
CK