[Wizdum]

737-800? Probably one of the most reliable aircraft produced by Boeing.
Maintenance, it always comes down to maintenance.

[RummyChick]

Or kamikaze suicide mission. It would seem to me that the way this plane went straight down will leave few options as the cause and should be able to pin point the issue

[Mr. Jeeves]

I flew on a China Southern 737-800 from Singapore to Guangzhou in May, 2019 and the wings flexed so much I thought they were about to snap off on final approach. I swear the plane even looked rusty.

Chinese airlines seem to focus their maintenance dollars on the larger aircraft used for trans-Pacific and European flights.