[throwiforgtnlzy]

"Something else hasn't had a problem before so it must be okay" isn't proof of anything and a fallacy.

There are known unknown structural issues with 737 NG's (-6xx to -9xx non-MAX) beginning around 1995 that have never been resolved because they were assembled poorly and built with substandard "approved" components by subcontractor DuCommun but aren't so serious that they would necessarily cause an immediate, catastrophic failure. Instead, there have been an increase in fuselage damage and failures under heavy load circumstances such as hard landings, runway overruns, and potentially during extreme turbulence. Al Jazerra made a feature-length documentary about it and the tales of the whisleblowers, but because of the predominant anti-muslim bias in America, it has been largely ignored and dismissed by the mainstream. Even Wikipedia includes biased conclusions that Obama's DOJ rammed down the throats of media and countermanded the NTSB's investigations and statements. [0]

0. https://en.wikipedia.org/wiki/Ducommun#Faulty_parts_dispute_...

[kayfox]

This issue is the failure to latch the three latches on the bottom of the engine nacelle, each of which is capable of holding the cowling closed for an entire flight. These latches are supposed to be inspected each time they are used and if they are not latched they will not be flush with the nacelle and should be caught by whichever pilot does the walk-around.

So no, the most plausible conclusion is not a structural failure but that maintenance opened the cowling and then failed to properly latch it and that was not caught by the pilot who did the walk-around.