Not exactly because a hint contains information that may become obsolete. A directive that freezes a known good auto-plan until the next release will not become obsolete as long as you keep releases rolling.
What I’d like is the ability to hand postgres an execution plan, whether that is a plan I retrieved from Postgres’s own planner, or one I wrote by hand (possibly a mix of the two).
Give the API a scary name if you want, but getting 3 Am calls because the planner suddenly decided to go off the rails or seeing pages of convoluted SQL because in (current version) it’s what it takes to get the plan you need is not fun.
It’s long past time for database developers to accept that the high level is not always the right solution, it should be that in 95 or 99% of cases, and the better it is the better my life is, but sometimes you got to write exactly what you need.
Most language designers are fine with it and will allow either embedding or calling into lower-level language (down to hand-crafted assembly), it would be great if database devs could get on with that program.
That's called a hint :)