As a long time lurker I finally had to create an account to reply to you. Boeing was indeed extremely large and profitable. Building such a successful enterprise came from lifetimes of work with dedication to excellence in engineering, manufacturing, safety, etc. Unfortunately we are seeing that a decade or so of attacking these values is enough to destroy even a giant. I do not believe that we are seeing just a streak of bad luck. Off the top of my head, let's review a few of Boeing's recent big projects.

787 - Historically over budget and delayed. Failed static wing deflection test, showing how much we can trust the FEA work. In cockpit battery fires led to a historic worldwide grounding of Boeing commercial aircraft. A NTSB report blamed (in part) Boeing engineers for not considering worst case scenario for a lithium battery in a cockpit compartment that contained no fire suppression system. A grounding like the one OP linked is not unprecedented, it is of the 'the plane is grounded until it passes an inspection' type. The battery fire issue led to a 'all planes are grounded until Boeing has a fix.' I believe that this is the first time that Boeing had an aircraft grounded in this way. I believe it was 3 months for Boeing to have an FAA approved fix. Incidentally the 'fix' was a heavy duty sheet metal box around the battery, with a vent to outside the aircraft. I suppose time will tell how reliable a fix this is. Finally there have been issues with debris being left in fuel tanks, metal shavings in wire bundles, etc. Allegedly in aircraft delivered to customers.

737 MAX - A half-baked software bodge has left hundreds dead and all these aircraft grounded worldwide. This is the second time Boeing had a commercial aircraft grounded worldwide with no end in sight. As with the 787 there are issues with debris being found in "complete" aircraft, with foreign object material being found in fuel tanks AFTER the aircraft has left assembly and passed inspection.

KC-46A (Air Force Refueling Tanker) - Years late, over a $1B over budget. Egg on face issues like not having the (required) FAA approval for fuel pods and drogue system. Repeated issues where Air Force refused delivery because of... debris in fuel tanks.

Starliner Crew Capsule - multiple critical software errors that meant the capsule never docked with the ISS and was nearly lost.

There are some common threads here. Bad software for 737 MAX and Dreamliner. Foreign object material ending up in wings and fuel tanks over and over.

Finally there is good reading to be had about quality issues in assembly, parts being rejected as defective and then "disappearing." Whistleblowers are reporting that the "disappeared" defective parts such as tail assemblies are ending up on aircraft and being delivered to customers. It seems there is pressure from management to sacrifice safety for profit, pressure to approve designs (thanks to some really good lobbying, Boeing essentially gets to approve its own designs with minimal FAA oversight), pressure to keep you mouth shut about safety concerns (and retaliation if you don't).

These are not signs of a healthy company. By now I think that Boeing has slid into "all-around shitty." The above is my best recollection of news stories from years of watching Boeing, if I have made a mistake then I am happy for any corrections. Let me know if you would like links to any of the particular stories or believe that a [citation needed] is in order.