I think 1900 the average was about 45, although the distribution was very different because the infant and child mortality rate was many, many times higher than today. So if you got to 20 you had a good shot at 60 or older.
Brooks has a very good case for being the best defensive third baseman ever. And of course he's a stand up guy of the highest order. But the idea that he was the best every single year for 16 years is almost certainly wrong, and an artifact of a flawed Gold Glove voting system.
His numbers should be discounted because of an alien offensive context. That doesn't mean his scouting reports aren't legit. But 42 games is 42 games. David Newhan once hit .400 over 42 games. Hurricane Hazle once had a MLB 1.126 OPS in 41 games. Gonzales' 42 games should be treated like anyone else's 42 games.