From Baseball Digest in October, 1957:

The record he speaks of is his 60 HR in 1927. Among the reasons that the record won’t be broken are the fact that Ruth didn’t have to deal with the media pressure as he headed down the stretch that anyone going for 60+ has to, the fact there are fewer off days, the fact that there are now day and night games that could mess with a player’s rest schedule, and that most of the parks aren’t as easy to hit home runs out of as Yankee Stadium had been during Ruth’s day.

He implies that Ted Williams could if he wanted to, but that he doesn’t focus on home runs, instead focusing on being an all-around hitter.

Interestingly, Duke Snider and his ghostwriter Milton Richman also predict that if anybody did they’d be headed to Cooperstown for sure.

Roger Maris is not in the Hall of Fame…. but he did hit 61 HRs in 1961.