Despite these problems, W3C XML Schema is everywhere

Microsoft announced early At a time when Microsoft was under fire for selectively implementing W3C specs, Andrew Layman announced that Microsoft would support W3C XML Schema - before it was clear what that would really be.
Microsoft, IBM, Oracle, Sun, etc. Large vendors have provided the backbone justification for others to create W3C XML Schema-based tools, sprinkling WXS from databases to Web Services.
Lots of tools produce XML Spy, XML Authority, various data-binding tools (including Visual Studio .NET), and a raft of others can produce W3C XML Schema, helping developers work with it through graphical or other familiar interfaces.
Lots of tools consume Microsoft Office XML 2003 expects WXS for much of its XML functionality, as do many Web Services tools and lots of other software.