[danlugo92]

I didn't know SSDs were easier trivial to build compared to HDD, I suspected it for a bit after reading your original comment.

So that explains why only 3 companies make HDDs.

[thijsvandien]

SSDs are essentially just some chips (controller, flash memory, and often some DRAM cache) wired together, whereas mechanical drives have many moving parts operating within microscopic tolerances.

[wmf]

For SSDs the hard part is the controller and NAND and there are only a half-dozen companies making those parts. 90% of SSD brands are the same Phison controllers under the hood.