It's such a false economy. It's harder the first time. By the third or fourth time, it's free. And that's before you count the expense of making super dumb hiring decisions, which is what happens when you use virtually any other process.
Now take a more normal organization where the hiring pipeline is guided by people who treat it either as a sales process or a regulatory one. Those people are given their marching orders by executives that either believe or want it to be true that employees are fungible and readily available. The actual resources are allocated by middle management that are already resource constrained (thus the need to hire) and the people doing the interviews have never thought about it being something they can apply engineering skills against. Its a hard problem...
Also, I suspect your marketing department might prefer if you never downplay how hard it is ;)