You are right, you can only scale vertically for single query execution but given that cloud providers now have beefy machines available with TBs of memory and hundreds of CPUs, it’s not a blocker unless you are querying petabyte level raw data. Trino/Spark is still unbeatable in that way but in most cases, you partition the data and use predicate pushdown anyways.

You can scale horizontally if you have many concurrent queries pretty well, that’s what I was referring to.