Because the RPi is a budget SBC where the most common use case is running it off an SD card, and they apparently didn't consider a SATA controller a priority fe

Because the RPi is a budget SBC where the most common use case is running it off an SD card, and they apparently didn't consider a SATA controller a priority feature. For many users (maybe even a large majority), that assumption was correct. https://www.ti.com/product/TUSB9261 https://www.ti.com/product/TUSB9261 There's a purpose-specific part from TI that's probably incredibly well supported and easy to source. It instantly adds a little under $7 to the BOM at volume (yikes), and you're not even counting the hundreds of hours of engineering time that would go in to integrating it (double yikes). Trying to do it with an FPGA would be even worse in terms of cost and engineering time. COTS products don't fulfill every use case, and never will.