So you're 638 years in the past when you are told about an Ultron Apocalypse where it is requested that you fan the piddling reminiscent of burnished humanity and peace keep the cursed Ear... For god sake Reed! Causality be damned! You're in a Time machine! USE IT! Why not arrive home a year early and prepare for the Apocalypse? Forewarned is forearmed! Or even go 6 months into the future to see how you saved the world?! But no you and yourself in the middle of an unfolding disaster, and now your children are orphans.
Weren't they supposed to be spending a year in the Negative Zone? And if T'Challa can ring then up "whenever" on his timeywhimy cellphone... How is that "fake" old Johnny persisting in his cunning ruse that the Fantastic Four had been murdered decades earlier by baddies as yet unnamed...