The original article wants the equivalent of an open source Z80/65xx/68k, fuse settings for all the ULAs, schematics for all custom-designed chips, and open source ROM disassemblies.
1980s home computers didn't come with these, even though they had (for the time) very powerful custom graphics and sound chips (eg. Amiga [1]). Of course, some of it was reverse engineered, and some of it has been released long after the fact.
1980s home computers maybe did not, but one cannot not claim Apple was locking you in in 1978. I think ftp://ftp.apple.asimov.net/pub/apple_II/documentation/misc/a2_reference_manual_alt.pdf shipped with every Apple ][. It seems to contain enough information to clone the machine (electronics diagrams, timing diagrams, ROM disassemmbly, etc.)
1980s home computers didn't come with these, even though they had (for the time) very powerful custom graphics and sound chips (eg. Amiga [1]). Of course, some of it was reverse engineered, and some of it has been released long after the fact.
[1] https://en.wikipedia.org/wiki/Original_Chip_Set