The mistake that caused this question to be asked:
http://ask.wireshark.org/questions/10000/how-to-get-the-txt-file-back-to-wireshark
might be due to people thinking that the result of an "Export" operation is something that contains the raw data from the packets and thus can be read into Wireshark. (The question itself appears to have hoped that, even if it couldn't be read into Wireshark, it still contained the raw data, which, in this case, it didn't.)
Perhaps we should put the Export menu items for "as text" and "as PostScript" under a top-level menu item that more clearly indicates that the result of the operation will not be readable by Wireshark and can't necessarily even be converted into something readable by Wireshark?
The same applies for the "export as CSV" and "export as XML" operations; those aren't easily human-readable, but they're written in a form intended for programs *NOT* interested in the raw packet data (and not equipped to parse raw packet data) to process.