China's solar giants quietly shed a third of their workforces last year

Looks like there are just too many companies in general. In my non-expert opinion seems like it it was because the country was a little too gungho about making more solar so they said it would be one of the big groth areas leading to a bunch if new developments. Then because there were so many of them they started competing with eachother and driving the pices down until they were unable to continue.

I would recommend reading the article tbh seems like good if dry information.

Oversupply. They pushed the price so low that the government is trying to put pressure on them to normalize the prices.