This is actually a very naive statement. Even in XML, you have problems
with versions. For example, say in version 1.0 of my DTD, I use
<para>.....</para>
and in the next I use
<p>....</p>
How can the wordprocessor handle this? Obviously, because it's a
plain-text format, it's easier to update/repair, but the problem
remains.
The problem solved by XML+styleSheets is that of allowing people to
extend/create volcabularies to describe their data and formatting. I
personally use Word styles religiously, but many/most don't. From my
experience, the power of instance overrides is seductive: I hate to think
of the number of Word documents I've seen that use little more than the
Heading N set (on a good day), Body Text, and Normal.
That said, I really want named styles in AbiWord.