I don't think the point is that PostgreSQL is great for everything. But you may get by with a single piece of infrastructure instead of 7.

In most of the applications we build or maintain we use PostgreSQL + cloud storage. That's it. And it works very well, also for: storing JSON, full text search, as a queue, as a vector database. Other software may be better at providing those features, but I'm extremely happy we only need to understand & manage PostgreSQL.