Really????? !!! I am amazed! ... what a long way has Apple travelled
since!! .... trying to imagine a similar instr. manual for an ipad!!
From memory, you could get full technical details of the Apple II, as well.
I think it wasn't until the Macintosh that they started heading for closed systems.
IBM went the open approach and as a result had a lot of competition with cheap clones, sometimes of questionable quality or incompatible features.
The result was that IBM didn't get the sales they hoped for. Macintosh got the reputation of being more reliable, no compatibility issues, while being more expensive. So they didn't get the sales they hoped for either. The winner was the cheap IBM compatible computers.
IIRC, Macintosh also had the advantage of having an OS providing an API to a range of services, not just a disk API. This was before I even heard of OS/2 or Windows. Which in turn meant Applications had to support all the possible variations in hardware support.