Yes, it's also used to hide implementation complexity and diversity: the advantage of a standard (even a "weak" one).

> SQL is used to reduce network roundtrips.

What I mean is: the database has an API that allows the client to specify (almost) arbitrary complex queries and operations. Regular REST APIs don't support this. GraphQL also supports it. The client sending queries to the database is a great way to reduce network roundtrips. Key-value stores that only support get/put/remove/list require a lot more network roundtrips for slightly complicated operations.

> it makes sense to try a better language.

I argue that the language itself (the syntax) isn't the main problem: part of the problem might be that SQL (even with a better syntax) would _still_ have very similar problems: missing indexes / wrong query plans, missing encapsulation which results in a complex mess of entangled code, things that work fine with small data sets but are extremely slow with large data sets,...

RDBMS has matured? I feel like I'm seeing a new database pop up every quarter.

>> RDBMS has matured? I feel like I'm seeing a new database pop up every quarter.

RDBMS's have been in use for more than 50 years:

https://en.wikipedia.org/wiki/Relational_database

There are hundreds of implementations some of which are decades old:

https://en.wikipedia.org/wiki/List_of_relational_database_ma...

Oracle and several other companies' (some of which are now defunct or were acquired by other companies) primary products were RDBMS software.

New implementations do not indicate lack of maturity but perhaps the wide availability of tools and libraries to build RBDMS's and their utility.

Perhaps you are referring to database systems in general and not relational databases?

Right my bad, I was thinking of storage engines in general. And of course maturity doesn't mean lack of innovation - which is still happening in the relational space.