IBM chose the 8086/8088 largely because it was cheap, but also because they had a licence from Intel to build them in-house. The Motorola 68000 would have been a better choice, but IBM were building the PC down to a price. The 68K was an absolutely brilliant piece of forward thinking. Even though it was only packaged as a 16-bit part, the core itself was essentially 32-bit. When properly implemented, programs written for a 68000 could be transferred to the 68020 (which was 32-bit inside and out) and be 32-bit without modification. And this was in 1979, Intel wouldn't release its 32-bit 80386 for another 6 years and it would be at least another 10 after that before 32-bit computing entered the mainstream (Yes, I'm aware that there was Linux, OS/2 and NeXT, among others, offering 32-bit on x86 years before that, but it wasn't really until Windows 95 that 32-bit was thrust into the public consciousness). The problem with 68000 though, was virtually everyone took it at face value and implemented it as a 16-bit processor and ended up having all kinds of migration difficulties when 68020. Even Apple, who arguably had the most successful line of 68K-based machines out of everyone who used it, grappled with 32 bit cleanliness issues for years after they released the first 68020-based Macintosh IIs.