I doubt that all these YouTubers agreed to tell the same lies about Boeing. It was Boeing's lies and omissions that resulted in the deaths of 346 people. After the first crash, Boeing said nothing about MCAS, just "pilot error."
Boeing made sure that there was no mention of the MCAS system in their manuals. Even after the two crashes, they tried to lie their way out of responsibility. Watch the video I linked above. The FAA wasn't much help, either, letting Boeing inspect itself.

Having worked in quality assurance/control for many years, I can vouch for the fact that almost always after a product is accepted by the customers (the general public) product quality gets pushed into the background.

Quality doesn't put money into corporate pockets until there is a serious problem (door plugs blow out of the side of an aircraft, . . .). Then in order to make a visible effort to keep the customers and avoid the company being shut down, the corporate hierarchy pulls out, what they claim is, "All Stops" to show how their quality system is second to none! Meanwhile they terminate the senior management in their quality system, hoping that the customers believe that solved the problems.

I did work for Boeing years ago, but not in a quality capacity. I do remember in 1959 or '60 a couple of their 707's had a problem with one manufacturers tires so Boeing asked the FAA to ground ALL the 707's, C135's & KC 135's until it could be verified that the aircraft had tires from other manufacturers. All of their employees that had access badges for all shop, taxi ways and runways were ordered to inspect all Boeing 707's, C135's and KC 135s for the tires in question. Of course we had to record all tires serial numbers and tail numbers so Boeing knew that all the aircraft in question had been checked.

The Boeing Company used to be so overly redundant about records keeping that they recorded all details of every aircraft they built or modified. They could research and tell you how many shims of a specific part number had been installed and where on every aircraft they had built or modified. Every serial numbered part or assembly was recorded as to what aircraft it was installed on, removed from and where it was stored while it was not on an aircraft.

A landing gear strut had been unaccounted for for over 20 years and I had been tasked with finding it, wherever it was and it's condition. It took me only a week, and people had looked for it for years. I had to get a Security Guard to open up a Boeing building that he said nobody had been in for 5 years. Leaving no stone unturned, I looked in every place that was large enough that it could fit.

I asked the Security Guard about access to a balcony above the shop floor which had a locked doorway that wouldn't allow access. He said nobody has been up there in at least the 20 years he worked there. He had the key, opened it up, of course there was a 4 inch coating of dirt and dust on everything. I found a landing gear strut, and after removing about 10 or 11 hands full of dirt and dust, the Serial number was a match.

Admittedly "can't be trusted" is a bit of a generalization but the evidence is there to support it in this video as well as news reports, FAA reports, GAO reports, etc. The 737 Max is a good example of Boeing shifting from good engineering, to profit-based decision making. The FAA is partly to blame for allowing Boeing to self-certify although I wouldn't be surprised if the FAA lacks personnel and resources to properly inspect all phases of plane construction. Once again though, it shows how businesses cannot be trusted to "self regulate" when it comes to safety, quality control and environmental regulations. Without getting too political, it shows we need a third party (FAA, EPA, OSHA, etc.) to protect us.

The problem is worse... it's a systemic failure. There is a total lack of accountability. There can be a condo failure in Florida, and 100 people are killed, several hundred killed from Boeing air crashes, and no one's feet are held to the fire.

Company boards are pressing for ever increasing profits and there is no downside for their action. They, and those they employ, have to be held criminally responsible for their decisions. Only when this type of result occurs will you notice an improvement.

Without getting political, one of the few legitimate reasons for a government is to look after the long term interests of the people; they have failed in this regard. To reiterate, the problem is systemic.