I don't see how that matters. I knew Spider-Man's origin story by the time I was six and I didn't have a bunch of previous fims, a geek dad or the internet.
If you were talking about new International audience I could understand the argument.
I think sometimes people forget the sheer amount of ways in which kids become accustomed to these characters; there has been a similar conversation about Transformers in Box Office Mojo. These franchises go far beyond film in terms of reaching new child audiences, my nephews and niece know ten times as much as I did about Marvel and DC characters than I did at their age.
Edit: Okay, ten times is an exaggeration, but I was geek to the bone. They are just normal everyday kids.