>>A vehicle that size, in my opinion, could have but one purpose, i.e. escape. It would be a space-faring version of Noah’s ark.<<
Have you considered that it could be simple a heavy cargo transport vehicle? Or perhaps a type of personnel transport vehicle? Consider how small our continental area is in relation to the land space on the entire planet and then study the number of aircraft we require to shuttle Americans and air cargo from one location to another every day of the week. Why can’t another society have similar requirements to ours?
INTERESTING.
Not at that kind of size and not for any purpose contained to our own system. Again there was a series of calamities back several thousand years ago and the people living in the system would have had no way to tell if anything at all was going to remain habitable here.