Samsung revamped its budget and mid-range segments this year with the launch of the Galaxy A line. That move appears to have paid off exceedingly well, as three devices in the lineup were in the top seven best-selling Android devices of H1 2019.
https://www.notebookcheck.net/Global-smartphone-sales-numbers-show-the-new-Samsung-Galaxy-A-series-with-absolute-dominance-in-the-Android-space.434799.0.html
Apple's market share is sliding yet they still sell the most premium models by far...