I'm not convinced about that comparison. MongoDB entirely disregarded the relational model whereas bitemporality—as envisioned by Snodgrass et al. and standardised in SQL:2011—is merely an extension/evolution of it.
> it would be cool if e.g. Postgres had fast native support for bitemporal fields in a way that makes them accessible without changing the whole paradigm
100% agreed with you there. And there has been various work on patches & extensions in this area previously. Unfortunately I'm not sure Postgres' internals will ever be able to flex hard enough to deliver a decent "default choice" experience. At least not until some other system has proven the UX is really worth the effort (which I guess MongoDB did similarly achieve with native JSON handling).
> it would be cool if e.g. Postgres had fast native support for bitemporal fields in a way that makes them accessible without changing the whole paradigm
100% agreed with you there. And there has been various work on patches & extensions in this area previously. Unfortunately I'm not sure Postgres' internals will ever be able to flex hard enough to deliver a decent "default choice" experience. At least not until some other system has proven the UX is really worth the effort (which I guess MongoDB did similarly achieve with native JSON handling).