You're vastly overestimating Silicon Motion's market share. Samsung, Micron, Western Digital, SK Hynix(+Intel), and Kioxia all use in-house SSD controller desig

You're vastly overestimating Silicon Motion's market share. Samsung, Micron, Western Digital, SK Hynix(+Intel), and Kioxia all use in-house SSD controller designs for at least some of their product line. Among second-tier SSD brands that don't have in-house chip design or fabrication, Phison is dominant for high-performance consumer SSDs. Speaking about SSD controllers in general: they do use off-the-shelf ARM CPU core designs (eg. Cortex-R series), but those are usually the least important IP blocks in the chip. The ARM CPU cores are mostly handling the control plane rather than the data plane, and the latter is what is performance-critical and power-hungry when pushing many GB/s.