Joe,
So it's not a slam dunk that you have the rights you think for every
I-D; you definitely don't have those rights for IDs
We're NOT talking about rights that were transfered from the document
author to arbitrary third parties here, but about rights that were
given to the IETF ("IETF contribution"), and which have never been
time-limited.
So archival and making accessible I-D contributions past the "expiration"
of an I-D is perfectly legal for the IETF, unless the I-D contains an
explicit copyright notice to the contrary (most I-Ds from 199x do not
seem to carry any copyright notice at all).
Where you are _correct_ is, copy&pasting parts of such an old I-D
or the whole document into new documents will in fact require contacting
the original author(s)/copyright holder(s) and obtain permission,
the Note Well provisions likely will not be sufficient, at least for those
old I-Ds. (it is not just a matter of courtesy, but a requirement).
I assume the latter is what rfc5378 is supposed to fix.
-Martin