Boing makes the plane. If they choose to contract out portions, they are responsible for managing the subcontractors; which includes quality control.

It's telling that they've got their reputation at the point where any time there's a problem with an air plane people assume it was them.

I was about to ask. We'll have to wait for information on which component failed here.

If all Boeing planes are questionable, it's reasonable to ask what the US government will do about it. They're the definition of too big to fail, but at the same times lives are very directly in the balance.

The core issue causing the quality control issues with Boeing is actually that they are outsourcing more and more of the design and manufacturing of their planes, and then squeezing their contractors, knowing that their contractors don’t have any other options, aerospace is both regional and consolidated. Boeing will gladly point out whenever there is a failure that it is the fault of the contractor that designed the relevant part or system, but it’s generally not that the contractor was incompetent, but rather that they were given an unreasonably tight budget and forced to deliver something.