"Kildall, meanwhile, often didn't even seem certain he wanted to be running a business in the first place:"

I should mention Gates wrote the Open Letter to Hobbyists. Of course, this was before "open source" or "free software" even was a term. At the time, CP/M had a "BDOS" supplied by DRI with the OEM having to write the "BIOS". There were firms such like Lifeboat which had writing the BIOS as part of their job.

Thinking about it, I wonder if it would have been feasible for Kildall to work on CP/M full-time at Intel and release CP/M source to public domain instead. It would be nice if CP/M was the first thing ported to 8086 back in 1978 for example.