Amiga Workbench was essentially derived from TRIPOS (https://en.wikipedia.org/wiki/TRIPOS) which despite being in research since 1976, had its initial release in 1978.
As far as I can guess: that is why Amiga Workbench 32bit time "EPOCH" begins on January 1st, 1978.
Despite that, Amigas were still resilient not just to Y2K problems but also Y2K8 problems and of course also no y2k38 problems. Further reading on Amiga time epoch issues here: https://amiga.de/diary/developers/y2k.html
What remains a "mystery" to me is why Linux which had its initial release in 1991, chose 1970 as its 32bit time epoch? I would hazard to guess, Linus always knew he was writing a bad clone, so rather than fix problems, or at least set the clock forward (e.g. set Linux epoch to 1991) to ignore problems a bit longer he became "problem compatible" with UNIX.
IMHO, Andrew S. Tanenbaum was too kind in his chastising on Usenet way back when (https://en.wikipedia.org/wiki/Tanenbaum–Torvalds_debate). Linux, in no small part, set back computational research decades, by choice of its 32bit time epoch alone.
As mentioned elsewhere, not all UNIX variants derived from real CSRG/BSD provenance have rested on their laurels. OpenBSD 5.5 released in 2014: already professed to be ready for 2038.
Many (most? all?) Linux distributions, remain vulnerable to 2038 time problems, even today in 2023.