That cheapest COTS block also has the advantage of being battle tested by the big customer base.
Since you presumably have pretty good contacts into IBM: ever asked if they'd consider pooling resources with other vendors around their interconnects in an open forum?
Not sure if DDR4 (or USB, or even PCIe 4.0) silicon is a huge differentiator for them, and those protocols all thrive on interoperability: no need for IBM (or Marvell, for example) to figure out all the issues with real world peripherals on their own.
Since you presumably have pretty good contacts into IBM: ever asked if they'd consider pooling resources with other vendors around their interconnects in an open forum?
Not sure if DDR4 (or USB, or even PCIe 4.0) silicon is a huge differentiator for them, and those protocols all thrive on interoperability: no need for IBM (or Marvell, for example) to figure out all the issues with real world peripherals on their own.