On the other side of the coin, I'm intrigued as to statements that those making decisions are well aware of the airworthiness issues. I would bet that either through ignorance, turning a blind eye, or just plain incompetence, the state of every aircraft on the line is not fully available to the person making the decision.
The situation can be further exacerbated, by the variety of agencies involved in the maintenance, and the communication problems that arise.
The project management process outlines specific tasks to be completed, and whoever deviates from that, and delays an aircraft from being back on the line, or ready for crew-in, is open to pressure from all sorts of places. The little things get missed, and can add up to something altogether more serious.
Add to that a PTs/CAMOs who are old school, with perhaps a lack of knowledge of the regulations, who trade off seemingly innocuous things to save time and money etc. and it amounts to a Human Factors maelstrom. The examples are out there!