[Someone]

When Safari came out, I happened to just have looked at the Mozilla code. A significant part of the "scale of what Mozilla had" was due to the design decision to couple the major browser components using a home-grown (and, hence, included with the sources) clone of Microsoft's COM.

To make matters worse, unlike Microsoft's version, the Mozilla version needed to support multiple OSes and multiple compilers.

Because of that, I believe Apple's claim that the choice for KHTML was on technical grounds.

(I don't remember whether Mozilla already used XUL at the time. If so, that could have been another argument for choosing KHTML)