The movies of the Marvel Cinematic Universe have established the common procedure to place little scenes after and during the credits sequence, in order to hint at future movies or to give hardcore fans recognizable things to adore. With The Avengers, their first big intra-universe crossover movie, this concept was then further played with by placing a (more or less) relevant mid-credit scene into the credits and a rather irrelevant (or humouristic) scene at the end of the credits, an approach employed by the following MCU movies from then on.
However, Avengers: Age of Ultron, was notably missing a 2nd post-credit scene, it only had the normal mid-credit scene showing an Infinity Gauntlet-acquiring Thanos (as far as my limited understanding of those matters allows me deduce). Now while I couldn't care less about those scenes personally, the absence of such a scene was rather notable, seeing that this is yet again an instance of their flagship sub-franchise which one would have assumed to drive the whole post-credit scene mess even further ad absurdum. But rather than that they went a step back.
So I would like to know if there is any official word or strong evidence why this decision was made to limit it to "only" one classic mid-credit scene. Has there been a strong aversion to the trend of multiple post-credit scenes in the public to which they reacted? Did they just want to take a step back to a more humble approach and the multiple post-credit scenes were just an experiment? Or was this maybe even to deliberately mess with an audience that has been trained to look out for those scenes as part of the movie experience?