The people who signed the SWA contract promising a big, new engine and agreeing to a penalty if cockpit retraining were necessary did this.
The people who made it beyond debate that they penalty not be paid did this.
The people who installed a system where safety was merely a set of obstacles to overcome on the way to production did this.
This is already a classic study. The engineers are handed a series of hard parameters and told to come up with something. Their solution is brilliant: develop a system by tapping into an existing system; normally, this would cause a huge problem, since the existing system wasn't built for that, and, in effect, you're relying on a single sensor input to move a secondary flight control, but, hey, with small adjustments that can easily be overridden manually and countered by primary flight controls, that's not a problem. So it passes the regulatory hurdle. Then in testing, surprise surprise, we're going to need more authority. Well, you know safety, in for a dime, in for a dollar.
Sure, Engineers "did this". They were given a design, a serious of hard obstacles, and some time, and they worked around to find a solution in keeping with the priorities set by management. They built an aircraft even more successful than the MD-11 turtle.
I do like it when companies start calculating the cost of everthing, setting up internal billing schemes and bureaucracies to keep track of such things. It's a useful way to drive up costs and then that work to another company with more efficient accounting practices.