Boeing has been having issues going back a lot further, since at least the 787 Dreamliner. It's just gotten a lot worse with the 737 Max.

The problem is that the FAA allows them to use "Designated Inspectors" to ensure their compliance, which are Boeing employees, not independent FAA staff. And the FAA is still allowing them to fly despite there still being serious known flaws (being unable to run the anti-ice system for more than 5 minutes without potentially damaging the engine).

It's also probably why their only real competitor, not being based in business-friendly safety-regulation-hating America, hasn't had similar problems.

In a properly regulated market, the FAA never would have allowed 737 Maxes to be certified for use, or it at least would have grounded them once issues became clear. Instead, they treat Boeing as "too big to fail" and don't want to upset the travel market in the way that grounding large numbers of planes because of a safety concern.