The "mirage" of CMS generality

The creator of Rails has a nice aphorism in his blog today about the ever-elusive general-purpose CMS:

The more expensive it is to create fresh software, the more appealing the mirage of generalization will appear.

Of course, many religious wars in software architecture (including the one between Rails and J2EE) seem to boil down to differing attitudes toward generalization, so maybe the apparent wisdom here is itself a mirage. But it rings true for me.