Awarding work to the lowest bidder s a normal practice and not an excuse for lower quality. When you have a contractors and subcontractors, you need to ensure that the contractors are complying with requirements. Of course, if requirements are wrong, contractor excuse won't fly either. Regardless of what you pay your contractor, you are responsible for ensuring quality. Boeing can't blame it on a contractor. That dimming is discovered when the plane is in service tells me something is amiss.
Please don't put words in my mouth. I specifically noted that I am not making such a claim, that some people might, just as some loyalists of Boeing and Airbus do everything there is a delay or some issue involving the "other".

Even raising a question does not mean that some part is going to fall off. Issue it raises is did Boeing exercise due diligence in determining not just system level requirements but in detailed design. Clearly in this case it did not, nor did it discover that their claim was not met in finished unit until after it went into service. We don;t know whether Boeing was as careless about other things. Probably not, but we don't know. If they were sloppy, cowling may indeed fall off. Not saying that it's time to pull everything off an aircraft and introduce an inspection regime.