It's very true today. The problem discussed here is performance on complex queries (e.g. subqueries), and the query planner plays a huge role in that. The Postgres query planner has various issues. Here are two recent posts talking about planner issues:

https://medium.com/@rbranson/10-things-i-hate-about-postgres...

https://www.cybertec-postgresql.com/en/things-could-be-impro...

Also JIT compilation, while very nice and a step in the right direction, is very barebones at the moment, hardly achieving its potential. Here's a long todo list of what and how to make efficient use of JIT in postgres, by the main author of the feature. https://twitter.com/AndresFreundTec/status/10025899696161996... Postgres release 12 did not add any JIT related improvements, and as far as I know no work has been done on it on 13 either.