Just putting my 2¢ in:

Repeat after me: There. Are. No. Silver. Bullets.

XML is a tool, nothing more.  A relational database is a tool, nothing more.  Fortran is a tool, Python is a tool, Perl is a tool, blah, blah, blah.  None of these will solve world hunger, nuclear proliferation, climate change, or the cost of car insurance.

Those of us who have been in the data management industry for several decades certainly understand this, as do those of us (well, "you") who have been in product development for many years.  But the software biz seems to be one of those where every generation insists on its right to make the same mistakes we made 40 years ago instead of learning from our experimentation and making all new mistakes.