Clark Kent, depression-era farm-belt Child of Privilege.
Steve Rogers, tenement Child of Privilege.
Jaimie Reyes, mechanic's son, one generation removed from the tin shacks, Child of Privilege.
Ma Hunkle, tenement Child of Privilege. Jim Corrigan. Ted Grant.
Ben Grimm. Sue and Johnny Storm. Clint Barton. Pietro and Wanda Maximoff.
Lot of the early ones, it's impossible to tell how self-made they were, to be honest, but a good amount of 'engineers' and 'scientists' of the 60s clawed their way out of the ghetto. Look at Richard P. Feynmann.