> In the 2000s, the conventional wisdom selected MySQL because rising tech stars like Google and Facebook were using it. Then in the 2010s, it was MongoDB because non-durable writes made it “webscale“. In the last five years, PostgreSQL has become the Internet’s darling DBMS. And for good reasons!
Different DB's, different strengths and it's not a zero sum came as implied. MySQL was popular before Google was born - we used it heavily at eToys in the 90s for massive transaction volume and replacing it with Oracle was one of the reasons for the catastrophic failure of eToys circa 2001. MongoDB gained traction not because it's an alternative to MySQL or PostgreSQL. And PostgreSQL's marketshare today is on a par with Mongo and both are dwarfed by MySQL which IMO is the true darling of web DB's given it's global popularity.
...Along with replication and being joined with the hip to PHP. As to installation, there was a point in time in the early 2000s where you could sudo to root, type 'mysql' and be talking to a live MySQL on most Linux distros that I used. No wonder a lot of people defaulted to it.
sudo apt-get install mysql-server mysql-client
sudo -i mysql
EDIT: Of course, at that time, there was no Ubuntu teaching everyone to sudo all the time, so drop all instances of sudo and add a su - at start ;)