Exactly. This is what is not coming out in most of these discussions. 1. Boeing took a great design and by moving the engine forward towards the nose of the plane and on a different position of the wing than what all previous testing had been on, changed how that design worked. 2. Boeing then skipped necessary testing, claiming it was an incremental change, not something that effected the overall design. They did this to keep costs low.

Boeing cut corners for costs and the FAA allowed them, in large part because they don't have the people power to do a lot of this testing. People died and faith has been lost in the US's oversight of airlines. This is a clear problem.