The trailer for to explain the secrecy. Many believed the title would be revealed at the very end of Infinity War, and when that didn’t happen, the speculation kicked in and has been driving the narrative ever since. Kevin Feige has previously said that all of the secrecy regarding the title has backfired on them, which would make the decision to further hold off on the reveal all the more surprising.
If Marvel does decide to release the Avengers 4 trailer without revealing the title, they potentially put themselves in position for a ton of backlash to the trailer as a whole. The trailer could show everything fans have been hoping for, but ending it without a title reveal would take some of the attention away from the trailer itself and into the bizarre marketing tactic that would be. Not only would it be strange from a marketing perspective to show a trailer for a movie without an official title, but it would also directly contradict what Feige had to say about the reveal earlier this year. He said the title would be revealed with “however we launch that film,” so it would be quite surprising for Feige to go back on his word.
The Avengers 4 title is anticipated not only out of curiosity for what it will be, but also so the secrecy around it can finally stop. Revealing the title before or with the trailer is the perfect time to do so, and if Marvel doesn’t capitalize on that chance, it makes it unclear when they would decide to reveal it. Unless the title also manages to spoil Captain Marvel in some way, there is no advantage to holding on to this secret any longer. But, we should know sooner than later whether this Avengers 4 rumor is true.
Source: Steven Weintraub