An even more plausible theory, I trust.
Ten years plus ago, Apple sent somebody to clean up the downloads site. Convert it from a couple of IIci running A/UX with downloads over FTP (yes, this is what Apple offered circa 1993) to an HTML site capable of serving more concurrent users. That clean out removed System 5 (which was available from the old FTP site) but most content remained. I used the old FTP site and I can't recall seeing anything older than System 5.
A few years later, Apple performed a clean-up of the HTML downloads and created a legacy site. I noticed that a few System 6 sub-releases were removed, but all of the interesting stuff remained. Some stuff was also removed from the FTP developer site.
I doubt, however, that Apple removed system software for the 128K and 512K for the simple reason that it was never there. Lisa, Mac XL, 128K and 512K software was available on developer and service CDs for many years. Perhaps somebody with a MacLink account can remember what was available there?
The theory that Apple don't release some OS versions (esp. 7.1) for licensing reasons has been floating around for years. I don't follow it. System 7.5 is a superset of 7.1, and there are no features in vanilla 7.1 that are not present in vanilla 7.5.x.
Ten years plus ago, Apple sent somebody to clean up the downloads site. Convert it from a couple of IIci running A/UX with downloads over FTP (yes, this is what Apple offered circa 1993) to an HTML site capable of serving more concurrent users. That clean out removed System 5 (which was available from the old FTP site) but most content remained. I used the old FTP site and I can't recall seeing anything older than System 5.
A few years later, Apple performed a clean-up of the HTML downloads and created a legacy site. I noticed that a few System 6 sub-releases were removed, but all of the interesting stuff remained. Some stuff was also removed from the FTP developer site.
I doubt, however, that Apple removed system software for the 128K and 512K for the simple reason that it was never there. Lisa, Mac XL, 128K and 512K software was available on developer and service CDs for many years. Perhaps somebody with a MacLink account can remember what was available there?
The theory that Apple don't release some OS versions (esp. 7.1) for licensing reasons has been floating around for years. I don't follow it. System 7.5 is a superset of 7.1, and there are no features in vanilla 7.1 that are not present in vanilla 7.5.x.