I think this metaphor is a bit misleading. If you wanted to contrast work at different levels like the author does, the metaphor would be "cake mix baking" vs.

I think this metaphor is a bit misleading. If you wanted to contrast work at different levels like the author does, the metaphor would be "cake mix baking" vs. "producing cake mixes". The metaphor above contrasts two different ways, but both are to make cake (output at the same level), where the one using raw ingredients spans multiple levels and the one using cake mixes stays at a higher level. One of the authors points is, that you cannot solely stay on this higher level.