"Bob Seger, John Mellencamp, Bruce Springsteen, and Tom Petty"
One is from Detroit, one from New Jersey, one from Florida and I don't know where Mellencamp is from. Some geographic concept of "heartland". I'd see all four as "electrified singer/songwriter rock", a music that is not totally anti-urban, yet avoids fashion and retains a rural foundation with lyrics that are not so much escapist as they dwell on everyday life. There are lots of other artists in that vein or even bands such as Drive by Truckers which always get lumped in as "Southern Rock", but have more to do with Tom Petty or Neil Young than Lynyrd Skynyrd or Molly Hatchet.