All good points. The better Golden Age and early Marvel stories were set on a world recognizably like the real one. The recent comics I've skimmed through seem to show a world where normal humans are the exception. There are so many mutants and costumed heroes and alien races jostling each other that the stories tend to look like a New Year's Eve party. This stuff obviously has its appeal, but to me it actually loses much of its sense of wonder. One person who can fly is amazing; thirty different people who can fly is a commonplace.
It's worth remembering that, as you say, Golden Age writers and artists were raised with ideals from an earlier time. Most of today's comics are still mining concepts from the 1930s and 1940s, tweaking them to give them a surface gloss and changing a few details to make them seem more relevant.