A really great feature that the Oracle database has is ability to provide hints to the planner. Is there anything that prevents PostgreSQL from adding this feature?

edit: Googled it, looks like PostgreSQL maintainers just have an opinion that hints are bad and the planner is good enough:

https://wiki.postgresql.org/wiki/OptimizerHintsDiscussion

There are "Explicit JOINs" but I'm not sure how useful they are:

https://www.postgresql.org/docs/current/explicit-joins.html

It's unfortunate that it comes off as if maintainers think planner is good enough, because that is demonstrably not true. And from my discussions there is wide agreement that the planner will never be perfect. But agreeing that it's something that needs work is not enough, someone actually has to do the work too. Reality is that implementing any feature to PostgreSQL quality standards is hard work.