That was years and years after they had already committed "the worst mistake they could have done", which was not buying Microsoft early on when they had the chance. This should be immediately obvious, as you're here complaining about people confusing Windows with PCs. After that, their failure to secure exclusive rights to Intel's x86 chips, their inability to keep up with all the clones on the market, and the missteps of the PCjr and OS/2, the eventual sell off the PC hardware business was inevitable.