You are pedantically correct but technically wrong, as even optimized postgres is going to suffer on analytical patterns without extensions. With extensions (DuckDB or Citus) you can do large aggregations, but regular postgres at medium/large scale (billions of rows, 100s of GB) starts having a lot of foot guns and complex babying to do analytics. A bunch of indexes and you'll be fine though.

> But there’s nothing stopping you from building out your data warehouse in Postgres or MySQL.

Other than money and time.