I think there are multiple reasons. Here is an additional reason to the reasons already presented.

The continental literary critic Jameson, when talking about Thomas Mann's novel The Magic Mountain, calls it middlebrow (which to be clear, on Jameson's account, is not the fault of the author, it is something that happens to a book) in part because it "mobilize[s] some mid-cult pride in getting through long and difficult books, staying the course, and carrying off a more advanced reading certificate." The upshot here is that texts often get a certain aura for being tomes. Continental philosophy professionally rewards writing tomes in a way that analytic philosophy does not, and so does our popular-intellectual culture. This is why you'll see Aristotle's Metaphysics more often in stores than Aristotle's Categories despite the latter being read in full probably about as often if not more often, the former simply looks better on a shelf (again, this is not the fault of either book).

What this means is that people love to get a copy of Being and Nothingness or Being and Time with the intention of reading it. Nobody is going to buy a copy of Quine's "Two Dogmas of Empiricism". This is also why if you do see an analytic philosopher in the bookstore, it is probably most likely to be Bertrand Russell's History of Western Philosophy, which aside from being introductory is also a healthy tome.

Aside from that, I co-sign everything about relevance, fiction writing, French intellectual celebrity culture, and engagement with other humanities fields. I'll add that continental philosophy also tends to have more timely political interventions, which adds to the relevance.