It's an achievement - just one I have no interesting in following or caring about despite thinking a lot of the Marvel properties are cool. I liked the original Iron-Man when I saw it, unaware it was the first step into the MCU, and never had any real interest going forward even when Nick Fury shows up at the end. The Incredible Hulk didn't really look interesting, and I didn't like Iron-Man 2 whenever I saw it. I had no interest in Thor, Captain America: The First Avenger, or Marvel's The Avengers. It was around the leadup to Age of Ultron that I finally watched both Captain America films and Iron-Man 3 and didn't like any of them. After hearing how much praise was given in particular to The Winter Soldier, it seemed pretty apparent I wasn't jiving with what they were doing. I randomly saw Guardians of the Galaxy and enjoyed it, but never saw the sequel and have seen nothing else but a lot of trailers and clips from other films.
It's hard not to be a little cynical toward it from the outside - the fervor for what's next is crazy, and its just non stop. I'm not sure an entire universe should hinge on post credit teases. It seems harsh to critique them for all feeling the same, but that's how they appear. Its like watching the doughnuts on the conveyer belt getting glazed at Krispy Kreme when you see the marketing. There's basically two character types, and they both just quip slightly differently which is off putting for however many characters there seem to be now. All this to say, for them to pull it off and have as many people entrenched is remarkable - just look at the state of DC's movies in comparison from a point of continuity... or how the same parent company has butchered Star Wars.
I can't say I won't watch any going forward, but I like Spider-Man and haven't watched any of his three solo movies yet so I don't know what it will take to drag me back in, I've watched the formula and I've had my fill - but I am genuinely curious to see how long it can go on because people seem to eat it up.