Brooks spends some time discussing these issues in the book, and I'm pretty much aligned with him:

Nobody belives in "a priori design" and I somehow doubt that anybody did. Brooks points out that the original publication of the "waterfall model" was meant as "how not to..." and people got that wrong.

But cathedrals are not about a priori design, they are about style, elegance, economy of means and coherency of design.

But my point in the piece is that the lost generation doesn't even know what a cathedral is in the first place, having grown up in the bazaar.