These shipping companies employ maintenance crews that have very little knowledge. Sadly, the wages and conditions are poor, maintenance staff unskilled.
For decades I've worked for offshore drilling companies, working on a drillship, when the drill bit is spinning through the seabed many kilometres below and the ship is on dynamic positioning, if there's a mechanical problem you want it repaired urgently. Our maintenance teams are remunerated well, only the guys who are well trained can be employed.
These huge cargo ships, travelling at speed through congested waterways, you want mechanical issues resolved immediately.