But UUIDv1 did exist for many years before UUIDv2, v3, v4, and v5 were all built and many years before this final approval of v6, v7, and v8. Even if the varian

But UUIDv1 did exist for many years before UUIDv2, v3, v4, and v5 were all built and many years before this final approval of v6, v7, and v8. Even if the variants don't "supersede" each other, live side-by-side and aren't meant to imply a version number like "semantic versioning" and a "proper" succession, the numbers still represent a progression of decades of real time between variant standards and the question remains valid how the designers of v4 especially missed/under-appreciated the changes/fixes/tweaks in v6 and v7 and didn't make such variants then? Hindsight is 20/20 of course, and it is easy to armchair quarterback how "let's keep the timestamp from v1 but use random data like v4" sounds like an obvious variant if you were in the process of designing v4 to "fix/replace" then usages of v1 knowing most of the trouble was just with MAC addresses and most of the advantages to v1 were time-sorting.