In the same way that China is stepping into RAM production, I suspect they will step into the gap for high capacity drives as well. The market abhors a vacuum and China is eager to fill it, even at minimal levels of profit. Chinese manufacturers have become very good at providing an acceptable level of quality at a good price, maybe not the highest quality, but acceptable for consumer use.
I can understand that incumbents may not want to overinvest in capacity, which could be financially precarious, but they are also putting themselves in danger by opening up avenues for competition. One more thing ruined by AI mania, I suppose.