Setting up a HA PostgreSQL setup might not be as easy as with some turnkey solutions where you just deploy three instances and then it (probably) works, but I'd still trust my data to a simple PostgreSQL replication setup over something fancier where the behaviour in failure scenarios is not as straightforward.
In simple cases, what people usually need is what I would call "operational" HA anyway; database servers going down unintended is (hopefully!) not a common occurrence, and even with a super simple 2-node primary/failover asynchronous replication setup, you can operate on the database servers with maybe a few seconds of downtime, which is about the same you'd get from "natively" clustered solutions.
In true failure scenarios, you might get longer downtime (though setting up automatic failover with eg. pacemaker is also possible), but in situations where that ends up truly mattering you likely have the resources to make it work anyway.
In simple cases, what people usually need is what I would call "operational" HA anyway; database servers going down unintended is (hopefully!) not a common occurrence, and even with a super simple 2-node primary/failover asynchronous replication setup, you can operate on the database servers with maybe a few seconds of downtime, which is about the same you'd get from "natively" clustered solutions.
In true failure scenarios, you might get longer downtime (though setting up automatic failover with eg. pacemaker is also possible), but in situations where that ends up truly mattering you likely have the resources to make it work anyway.