It depends how you interpret the video...
THE cause of the crash was the minor spalling on the inside of the ring gear, this seems 100% certain. Now the question is: how did this spalling happen??? For this they made this huge fault tree analysis and came up with the following possible causes:
A: by intrusion of small particles
B: by shockload
C: by pressure of the roller bearings
D: by fatigue
E: a possible combination of the above.
To counter this they;
A: Reduced the risk of particles entering the gearbox by the additional covers and to perform the work only in certified maintenance centers.
B: To counter effect of shock loads they installed monitor sensors on transport cases, remove gearboxes with "incidents" from the fleet and have maintenance done in certified maintenance centers.
C: To counter the effect of the pressure of the rolling bearings they have removed the version with the generally higher pressure from the fleet, reduced lifetime of MGB.
D: To counter the effect of fatigue they have reduced lifetime on MGB, reduced stress with only allowing the better bearings.
E: To counter the risk of undetected spalling they raised inspection intervals and installed better chip detectors.
Now with all those measures in place I think they covered all most likely causes of the accident. Is it a 100% guarantee??? No, but we will never have a 100% certainty with mechanical things flying through the air... If you additionally add up the fact that these gearboxes also have 100 of thousands if not millions of hours of flighttime I think it is currently even safer than when putting in a brand new gearbox design as some have suggested. I would get on one without hesitation.