modern dram and nand memory fabs are way more expensive to build and operate than legacy hdd spinning platter factories. Japan and Germany couldnt sustain the capital cost while sustaining a price war, hence why today only three big manufacturers left to corner the market.

the other thing is that for years HDD demand going down with shift to SSD, likely a lot of underutilized capacity at those Hdd factories. too bad malaysian ones all closed down edi due to chyna.