If no computers that can read punch cards exist, then we have no means to know what information is stored on those cards. Perhaps they also have Zip, Jaz, Syquest, or other large-capacity storage systems. Current trends indicate that Zip discs will probably become obsolete sooner than CD-Roms, because laser technology is currently favoured over magnetic films used in floppies and Zip or Jaz discs. We have already seen the demise of the vinyl record, and the near-loss of the audio tape, as the price of CDs came to match our incomes. Looking back at data storage systems over the past two decades, it is reasonable to expect many more changes.
Paper takes space, but at least it can be read even with the evolution of new technologies.
Government archives are clogged with mostly inaccessible data and statistics that were only stored on now-obsolete punch cards or floppy discs. Few libraries had the foresight to keep some old computers that could read the contents of their own archives. The major exception to the loss of data through changing technology is the microfilm or microfiche. Most of use would rarely use these now, but they are in fact durable forms of information storage. They also greatly reduce the space need to physically store the files.