This argument (don't re-write) sounds great to laymen and managers because they see "the code" as the sole artifact of the development effort. The flaw here (known to almost any developer) is that the code itself, the physical files and such represents the work of developing an application as completely as a photograph of a boxing match represents boxing itself.

Evidence of this can be seen in the many examples of companies "buying out" an application by taking only the source and attempting to run with it. The results are rarely, if ever, spectacular.

Most of the application is in the minds of the developers. Take away his source and ask a developer to re-write an application and you are guaranteed to get a better program. Why? Because by the end of the project you know more than you did at the beginning, and when you re-write the code from scratch you can leverage this knowledge on all of the code, not just the code you wrote after you learned these lessons.

In this way it is impossible to re-write something (unless you are starting with new developers as well), just like if you asked Stephen King to re-write (as in, re-type) The Shining...