Even using an assembler, (which we did most of the time), we would leave a pool at the end of each PROM (and they were PROMs with a 6 week lead time) so we could patch a bug and only have to change one PROM and not the whole set.

I'll draw heat for this but I think most business books are boring and/or suffer from survivorship bias.

The most interesting business book I've ever read was Creativity Inc, by Ed Catmull. He talks in depth about managing a business where creativity is the most important aspect.

The Start-up manual is good too, if a little drawn out.

I think you are right, I've read quite a few over the years but looking back I learned far more by interacting with peers and just getting on and trying things.