This will all change in Avengers: Infinity War and the followup, Untitled Avengers, when the Mad Titan comes to Earth to vanquish the galaxy of its mightiest heroes.
After all, without him there would be no Thanos and hence no Infinity War, so a cameo is the least they can do.
As Thanos is a character based on his comic counterpart, how much recognition creators of these characters get widely varies.
Since then, Thanos hasn’t really done much of anything besides have his attempts to have others bring him the Infinity Stones go wrong, leaving him stoneless still.