Okay, I will say this up front.....I am not familiar with Marvel comics as well as I am with DC. however, I do know this, the Phoenix force is an force of Destruction and Rebirth. The force can restore the depleted Mutant Population, but it can also destroy the world. Hence why the Avengers want to keep it from gaining a host......correct me if I am wrong.
So what happens if the Phoenix Force destroys the universe of marvel, and in a Phoenix like turn, remakes it. I know DC has a sales edge due to the new 52...could this be how Marvel responds? Reset the Avengers, the X-Men, the Fantastic Four, as to allow first time readers a chance?
As to the age of Ultron.......Justice League, or Avengers, need a powerful first foe after all.