On: A look at the die of the 8086 processor

[Gibbon1]

I think also a narrower data bus which might allow a smaller PCB with fewer layers. Used to be higher layer count PCB's $$$$.

Friend worked on a layout where they did the board design first and then designed the processor pinout to match. So they could get away with a small two layer board. Ground on the bottom layer and all the signals on the top layer.