Curious George writes:
Consider a Word Perfect 4.2 file from 20 years ago. You'll need
some effort today to open and read such a file. Because the format
is relatively simple, you can still read the text using any hex
editor. But recreating the page formatting maybe harder already.

Ok so a lot of converters do an incomplete job, but is this really so
complicated? Save a copy of the application(s) and maybe the OS that
ran it with the data. Between backwards compatibility and improving
emulation technology it might be more doable than you think.

I would say that most of these conversion problems have stemmed from
secret, undocumented formats. Formats like jpg and mp3, which are well
documented and have reference implementations available as free source
code, should be pretty well immune to the problems.