Some of what happens in Ragnarok towards the end felt to me like a way to round out a trilogy of Thor films, in much the same way that Iron Man 3 closed out an Iron Man trilogy without necessarily preventing the character from moving on and appearing again later.
At the end of IM3, we have the idea that the armor is almost like a cocoon, something that Tony leaves behind and grows out of. He doesn't need the armor to be Iron Man. We've seen him in armor since then, but that's still an important idea and a logical/inspiring conclusion to a trilogy of Iron Man movies.
Ragnarok is a bit like that for Thor. In the first movie, we have the idea that he is heir to the throne, before he is cast out. A lot of people thought that he might become King of Asgard at the end of the third movie, succeeding his father. Missing the eye is like a symbol of Asgardian royalty (sacrificing it to gain knowledge and wisdom).
All of that stuff happens in Ragnarok, though not in the way that people would have expected.
The movie also shows that Thor is Thor, with or without the hammer. That's a very similar message to what we saw with Iron Man as well. We've even seen it with Cap to an extent, and I'm guessing that the shield will be a big deal in A4.
The star forge scene in Infinity War reminds me a lot of the cave scene in the original Iron Man. It's about Thor building his own hammer, essentially. The hammer means more now, because it's not something that was just given to him, and now everyone understands that Thor is Thor regardless.
That's crucially important for the character to work.
In other news, Marvel Studios is really good at this character building stuff
