About ten years ago I stumbled upon an article by a computer programmer Hubert Tonneau, the author of the Pliant programming language. He argued against the relational database:
At that time I looked around to find similar opinions on the internet but found none. Moreover, when I repeated it to my colleagues I was ridiculed: "Nonsense, we abandoned hierarchical database exactly because it wasn't good, and relational one is better". But look around now, we are now in the age of NoSql, Redis, and Mongo databases. How did that happen ?
Ten years ago was the height of LDAP's trendiness. Today it quietly backs most large-scale authentication databases and technologies like Active Directory which hipster admins regularly cream their pants over. You aren't aware of this because old, functional, standardized technologies aren't the stuff of blogs.
How did we get here? Relational databases don't scale. Few organizations wanted to put the resources into supporting hybrids (separating hierarchical data). And it turns out that throwing hardware at a kludge like NoSQL makes more money in the short term.
So, basically, we got here by doing things as half-assed as humanly possible. That's the story of practical computing in general. In fact I could probably turn this into the fault of the Federal Reserve, given enough whitespace. But I'll stop there for now.