The incompetence was using Lithium NMC batteries in the first place for a stationary application.
Companies in the US and Japan developed NMC batteries because they had higher power to weight. And power to weight makes sense in vehicles to boost range, but in stationary applications that power to weight really does not matter. Because they focused on the NMC batteries, they did not develop the safer (but lower density) LiFePO4 batteries (but Chinese companies did). Because the US/Japan only has good NMC batteries they use said NMC batteries for everything even when the density is not needed and ignoring the fact that once they catch on fire they are almost impossible to put out, unlike the LiFePO4 cells.
China uses LiFePO4 in vehicles, and even Tesla used to put them in one model but because the batteries were not domestic the vehicles did not qualify for as many tax credits.
One wrong step of we need high density and ignore the fire risk, and don't develop anything else. Given enough installations of NMC batteries a fire WILL happen simply because any manufacturing issue and/or accident will start a fire, and once started it will be very difficult to put out.