Marvel can attempt to re-create the mood and feel of the classic period, but at the end of the day it will fail - in the same way that remakes of classic films fail. Try as one might, you cannot recreate that period. All those elements that made up the zeitgeist of that era are long gone.
Yes, there are long-time (and long in the tooth) fans, but not enough. Today's "readers" are a different beast. These are the people who helped video game profits exceed film profits for several years in a row.
Comics will eventually become a casual e-option fof those interested. Sad for some, but inevitable.