Streaming has been the story for the past couple of decades already. But once you accept the value of an event-first architecture, the benefits of traditional RDBMSes become much weaker.
A lot of work has taken place in the Kafka, Flink, DataFlow ecosystem but that still leaves a lot of work for the developer over a simple subscribe to query results.
I do think a lot of work has been done, but it all needs to move up a few levels of abstraction.
Our focus (Hasura) is on the last mile so that innovations on the data side (eg: materialize, ksql, timescale continuous aggregates) are “just obvious” to start building applications and services against.
Personally I find it much easier to write the code explicitly than try to understand what a query planner is doing, especially if performance is relevant. (That's not to say there's not plenty of room for improvement in the streaming world - but I'd rather have a helper library that I can use on top of the low-level API, than have to go through a parser and planner for every query even when I know exactly what I want to do) But I seem to be an outlier in this regard.
Plus you can stream db changes from postgres to kafka for those edge cases where you really need it
TLDR: if you're in a startup and thinking of building a distributed system.. DONT. stick with a monolith and spin out services as NEEDED.
Funny, my experience is the exact opposite. Materialized views and triggers are death by a thousand cuts with all their edge cases. Whereas if you just use Kafka for everything from day 1 then everything works consistently and you have no problems.