Well, there are three types of databases: Relational, Columnar, and finally massively distributed. They throw away different feature sets in order to handle a certain subset better.
The primary reason Relational databases are so friggin' strong is that they have a solid foundation and maturity. Most new "NoSQL" stuff is immature crap which should never be used in production for any kind of persistent data. But they are being used as such, and I do note that matures the products over time.
Tell me about it. I have been hauled into a project, where we are reimplementing a relational database using NoSQL. No idea why, other than the fact that they want to use NoSQL.
The primary reason Relational databases are so friggin' strong is that they have a solid foundation and maturity. Most new "NoSQL" stuff is immature crap which should never be used in production for any kind of persistent data. But they are being used as such, and I do note that matures the products over time.