> Instead, it has stagnated: Amazon holds on to an effective monopoly on the discussion of new books This is the main point. It is the same thing that Oracle purchasing MySQL. What once was a promising raising technology is nowadays stagnant. (Interest over time https://trends.google.com/trends/explore?date=all&geo=US&q=%... ) GoodReads could help to find better books to read. But, Amazon likes the current state wher…
Connecting Oracle's purchase with the MySQL's market share is a long stretch. Even based on that diagram, the decline started earlier than the time Oracle came into play.
The quality and pace of development of MySQL/InnoDB hasn't meaningfully changed (although one may subtly observe that with v8, they radically changed the release philosophy - patch versions now can introduce new features or break old ones). There have been low and high quality features developed, but that happens with any software. In order to get an idea of how MySQL was around 10 years ago, notice how by that time, MyISAM was (unfortunately) still something.
A simple interpretation of the shift in market share is that PGSQL hasn't been ready for wide adoption (historically speaking, it's been considered for a long time the slow and cumbersome RDBMS), until, after a certain functional threshold, it entered a virtuous circle of improving and getting traction.
Of course, it's also possible that people is taking distance from MySQL "because Oracle", but that doesn't constitute a technical ground.