Since The Avengers we have all wanted to see Hank and Jan join the MCU and be a part of its formation. But many of us were disappointed when they were nowhere to be seen and not be responsible for its creation.
Now we finally get to see them in the MCU with Ant-Man and yet, still, people are disappointed. Mainly for the fact that Jan (presumably in the 60's) is involved in a tragic accident with one of Pym's experiments killing her off rather early on and still not giving Janet, perhaps one of the most loved members of the Avengers, her glory on the big screen. Personally, I think the experiment doesn't kill her but greatly harms her making her leave Hank and causing their daughter Hope to resent Hank because of it. I don't like how many make assumptions to the worst possible outcome that Janet dies.
However! I have a theory that Janet may still have an important role in Ant-Man in the 60's and still be responsible for creating the Avengers, name and all.
Among the cast of Ant-Man is John Slattery who reprises his role of Howard Stark from Iron Man 2. And as we all know Howard is one of the founding members of S.H.I.E.L.D. and one other theory going around is that Hank and Janet may have some involvement with S.H.I.E.L.D. in the 60's.
Now, let's say that theory is true. Let's say that in the early days of S.H.I.E.L.D. Howard takes notice of Pym and his particles along with his heroic exploits and invites him and Jan up to the Helicarrier for a chat about things, such as the sudden development of super powered beings and their growth. Howard being the futurist that he is tells Hank and Jan that in the future he can see many other super powered beings coming up and seeing that HYDRA could pop up again and be a threat.
Then comes Janet's idea. She believes that there would be good people, like herself and Hank, who would use their powers for the good of the world, to protect it and others from harm.
The idea of Janet's is to bring together a group of of remarkable people and see if they can become something more. To see if they can work together when S.H.I.E.L.D. needs them to, to fight the battles that they could not.
Bam. And there you have it. Jan creates the Avengers initiative for S.H.I.E.L.D. thereby creating the Avengers team, name and all.
I think that would be a nice little outcome at least. What do you think?