Fresh blood

The fourth Avengers movie, scheduled for 2019, is also Phase 3’s last movie. Can we expect to see the same team in Phase 4, as well?

No. We cannot.

The change is happening as we speak, even as some of the older superheroes (such as Iron Man and Black Widow) are popping up all over the place in the MCU. The actors, unlike the characters they portray, do get older. Sometimes they  want to do something other than playing the same hero again and again.

RDJ has renegotiated his contract multiple times since 2008 "“ but I guess he won't do that any longer. Other actors are nearing the end of theirs. And we’ve already seen those who will replace them "“ with Benedict Cumberbatch already being called the new face of the MCU.

So this is not a rumor, but a certainty.