@kenshirriff I strongly believe the PS/2 was a failure because they went all-in on Microchannel, rather than have a transition period when their PCs would have both MCA and ISA slots.

All the other PC bus transitions had "bridge" motherboards with both buses. I remember ISA and PCI, then PCI and PCIe. IBM f-ed that up big time not giving people a chance to migrate to new peripherals.