> Isn't there value in the ISO imprimatur for ISO/IEC 19757-2 
> RELAX-NG and ISO/IEC 19757-3 Schematron?
> 
> Do vendors feel these standards are not worthy?

I don't know if I'm alone in finding this situation a little strange. How
can you have an ISO standard that is layered on top of, and
totally-dependent on, a specification (XML) that is controlled by a vendor
consortium? But I don't think that affects the answer to...
> 
> So what is holding vendors back from ISO-developed standards?
> 
The big software vendors all committed themselves heavily to XML Schema back
in 2000/2001 and have huge investments in it. The more you spend, the less
your inclination to change direction. Also, they see the big spenders in the
user community equally committed (or locked-in, if you prefer).

The fact that it's a spec from outside W3C does influence the thinking, I
suspect: W3C are perceived as owning the XML space and anything from outside
is seen as being disruptive. An ISO stamp of approval never guarantees
commercial success for anything, even if it adds respectability.

Michael Kay
http://www.saxonica.com/