Relational databases with joins and full SQL support are still unmatched in flexibility, and functionality like materialized views, aggregation pipelines (and table engines for Clickhouse) allows you to do everything that Druid does with aggregated summaries while still having all the other querying abilities.

Druid has a slight edge in data scale-out and indexed seeks but modern data warehouses are adding similar tiering features, along with with field indexing, full-text search, nested data records, and even in-memory rowstores for OLTP support.

They're all converging on the same feature set and eventually Druid will just become another data warehouse option, although I'd still recommend Clickhouse or MemSQL at that point.