Carl Erskine was washed up at age 31. Clem Labine was a relief pitcher who never threw enough innings to qualify for an ERA title, but he didn’t last very long - only 513 games isn’t a long career for a reliever. Ralph Branca, washed up at 28, as already noted.
Maybe those guys should have watched their pitch counts.
Labine had a few sparkling big shutouts as a starter -the game before Branca’s & the day after Larsen. I don’t think the answers would be any different from Gibson, Spahn, or Robin Roberts. There just isn’t respect for today’s starters from guys from 30+ years ago.(not for public consumption of course) I could only mention guys I asked.