Comment by smacktoward

There was also the fact that the IBM people working on the original PC had already established familiarity with Intel's architecture through their work on an earlier IBM product, the Datamaster (http://www.oldcomputers.net/ibm5322.html), which used the 8-bit Intel 8085.

David J. Bradley (https://en.wikipedia.org/wiki/David_Bradley_(engineer)) worked on both the Datamaster and the PC projects, and explained the reasoning behind the choice of the 8088 for the latter in an article in the September 1990 issue of Byte (https://archive.org/stream/byte-magazine-1990-09/1990_09_BYT...):

There were a number of reasons why we chose the Intel 8088 as the IBM PC's central processor.

1. The 64K-byte address limit had to be overcome. This requirement meant that we had to use a 16-bit microprocessor.

2. The processor and its peripherals had to be available immediately. There was no time for new LSI chip development, and manufacturing lead times meant that quantities had to be available right away.

3. We couldn't afford a long learning period; we had to use technology we were familiar with. And we needed a rich set of support chips -- we wanted a system with a DMA controller, an interrupt controller, timers, and parallel ports.

4. There had to be both an operating system and applications software available for the processor.

Points 1 and 3 both reference lessons learned from the Datamaster project -- #1 is about the desire for the PC to overcome a limitation the Datamaster's 8-bit CPU had imposed on it, and #3 refers to the fact that the 8086 and 8088 were close cousins of the 8085, so the IBMers wouldn't have to learn a whole new architecture from scratch.

It's not hard to imagine the decision coming down to Bradley (or someone else on the Entry Systems Division team) calling someone they knew at Intel and saying "we need a 16-bit processor as similar to the 8085 as possible that you can deliver in volume tomorrow. Whatcha got?"