Gaga is not a superstar She's barely even a celebrity now
Lady Gaga is a superstar regardless of if she's spammed on radio/spotify or not. Her name is still big enough to outsell most pop girls and score her a Superbowl halftime show
Pure album sales aren't really much to brag about unless you're Taylor or Adele.
They simply don't matter as much anymore. Hits are a bigger indicator of who is "big" right now. The Chainsmokers had a huge peak this year and opened with 9k.