The Marvel Cinematic Universe has peaked. I predict it will decline in quality quickly over the next few years. Captain Marvel was the turning point. The character is far too powerful; giving them the same problem DC has with Superman. They keep thinking they have to keep topping themselves by jacking up the power levels. Problem is, characters who are too powerful are boring. That’s why, in DC, Batman is FAR more popular than Superman.
I saw the exact same progression in comics. I collected comics from 1971 to 1991. I also got a lot of back issues, where I could see it even more clearly.
In Fantastic Four #18 (c. 1963),
it states that Ben Grimm (the Thing) had a maximum lift of about five tons (and it was shown that Super Skrull was, indeed, much stronger than Ben). It was also clearly shown that the Hulk was just a bit stronger than Ben. When the Kingpin was introduced, he was a Spider-Man villain; it was clearly shown that just by being a freakishly strong normal human, he was almost a match for Spidey in raw strength.
Then, they appeared to feel the need to keep jacking up the power levels. Today? They are mostly boring. DC went through the same progression with their characters decades earlier.
Kryptonite was invented by a Superman writer who realized his story was going to end on page two.