Is it that hard to implement? Supporting an additional UUID version in PostgreSQL sounds like the most trivial change to implement (compared to anything that touches core backend, table management, replication, query schedulling, and so on).
The patch is already written, it's on that page. The bottleneck in Postgres is reviewer bandwidth which is why it's been moved out of several commitfests.
I don't think reviewer bandwidth is the main issue for this patch. It's a 200-line change (considering C code, there's more in docs/tests), and the code is not overly complicated / sensitive (in the sense that it's very isolated and unlikely to break random stuff).
For me the main challenge was that it's still considered a draft (AFAIK). It may be unlikely to change, but if it does I'd rather not have to deal with persistent UUIDv7 data generated per some previous spec.
Also, if I really want/need UUIDv7, it's not that hard to create an extension that generates UUID in arbitrary ways, including the proposed v7.
It's slightly different from recommendations by draft RFC version (there's no counter), but fully within spec requirements. From practical point there's no difference at all.
