Judging by the graph there was a serious inflection point in 2008. Which seems about right from what I remember. So it probably should have been a headline long before now.
The 2008 inflection would have come from the financial crisis. Lots of large firms got hit by that, and a few went under. Since the plot is of _new_ licenses, it suggests that companies weighing the benefits of Oracle vs. one of the alternatives (Postgresql, NoSQL), went with cheaper.