Comment by eloisius

He explained that a bit here[1]. The project targets a world wherein existing computers have degraded to a point beyond repair and we have to scavenge parts that can be retrofitted. His reasoning is that under such conditions, parts that can be thru-hole soldered such as 8-bit z80 CPUs will be much more robust than surface mounted ARM chips.

1: https://collapseos.org/why.html