80 column support was key. More or less CP/M compatibility was also key. One thing the 8088 PC had compared with the 8-bits was rudimentary memory management

80 column support was key. More or less CP/M compatibility was also key. One thing the 8088 PC had compared with the 8-bits was rudimentary memory management in the form of the segment registers. This decoupled the OS and BIOS from application code in a way that was not possible on previous 8-bits. People forget that in the world before memory management that if you wanted to change the OS your only option was to do something like "sysgen" a horrible slow process where you re-linked the OS and all application code. IBM's OS 360 and DEC's RSX-11 had this concept. People hated segment registers, but the only other alternative was position independent code, like on the 6809. I would argue that this is worse, because it slows execution time.