> wait we're not in the nosql era anymore?

Kinda. It turned out, that for the vast majority of users, a single Postgres instance on a reasonably large host is more than enough. Perhaps with a read replica as a hot standby.

You can easily get 1 million transactions per second from it (simple ones, granted). So why bother with NoSQL?

> redis and kafka (and their clones) are ubiquitous, etc etc

That's a bit different. Kafka is a message queue, and Redis is mostly used as a cache.