Why are XML crowds older?

When marketing and sales people come to XML shows, they often ask why 
it's an older crowd than what you see at, say, a Java show or a 
Microsoft show.

Thinking of the people in the XML community whom I respect most, they 
seem to be on the older side too.

Any thoughts on the demographics of XML, and how it differs from the 
demographics of Java or .NET?

Jonathan