A TIFF reader that could read all possible forms of TIFF files seems
easier than a Postscript reader that could read all possible forms of
Postscript files. Just because Postscript doesn't define any
subprofiles like TIFF-B or TIFF-F doesn't mean that the problems are
analogous.
Besides, you can tell looking at a TIFF file which tags it uses --
they are clearly identified in the body. If there aren't going to be
separate versions of ps for different versions of postscript, and "ps"
means basically "anything you think is ps as long as a reader might be
expected to tell", then you might as well be consistent with "tiff"
and "gif" and other things too, and not expect there to be different
IANA-assigned types for those. While I'd much prefer specific
registration of current versions of those as "ps1" and "tiff5.0B" and
"gif89a", I'd also rather have consistentcy than to have some of the
subtypes version controlled and others not.
What it seems is going on is that people disagree in this forum about
the proper role of versions and format management, but, in the
interest of getting something out the door, the disagreement is being
swept aside. I guess that's OK with me too, as long as the issue is
actually resolved before this thing actually becomes an internet
standard -- resolved because the spec is ambiguous and the issue needs
to be addressed, independent of whether initial testers of the spec
think it is a problem.