It's classic Christiansen "Innovator's Dilemma" disruption. Market leading incumbents run by business managers won't assess emerging unproven new opportunities as being worth serious sustained investment compared to the existing categories they're currently dominating.
Yes, they eventually got it right post-Newton after spending a lot of time on the outside of the sp500.
So you're saying that they were somehow unaware of how new BIOS implementations were used in CP/M to port it to new systems?
And that they distributed the BIOS source code with every IBM PC... to make it harder for competitors to build compatible machines due to copyright claims?
And that they were somehow unaware DOS had largely reimplemented the CP/M design and API? (Though DOS's FAT filesystem was a successor to FAT8 from Microsoft's Disk BASIC rather than CP/M's filesystem.)