The only issue that I have with this top-most comment is that it presents PG as a silver bullet. But, there are a lot of different types of databases for a reason.
For instance, at my current startup, we employ at least 7 different databases (including PG). And, I don't say that to brag - each has a specific use for the problem at hand.
You have to consider the needs and trade offs of your specific project. And, if you can, try to isolate your storage behind some interface. Because often your needs will change.
(I say this with 20+ years of experience and over a dozen commercially-successful products in my belt)
Not disagreeing necessarily, but having many different databases has a cost.
Data has more value when combined, so a wise database choice also depends on what you already have. You can combine data from different systems (e.g. FDWs, which postgres has great support for), but something is usually lost along the way.
I think postgres is a good default, because it is good for a lot of things. But sure, if you make an informed decision otherwise, there's nothing wrong with that.
It is true, that you should not chose blindly, but a majority of use cases do require a relational database. You use one of specialized databases when you have a specialized use case.
The reason why Postgres is so popular here is because if you want to have an open source solution, Postgres is the best available. I'm sure there are better proprietary solutions, but even though it is free, PG is pretty darn close to them.
For instance, at my current startup, we employ at least 7 different databases (including PG). And, I don't say that to brag - each has a specific use for the problem at hand.
You have to consider the needs and trade offs of your specific project. And, if you can, try to isolate your storage behind some interface. Because often your needs will change.
(I say this with 20+ years of experience and over a dozen commercially-successful products in my belt)