First, some facts: there have been 641 hitter-seasons since 1871 where an OPS+ of 160 or higher has been achieved.
As the chart shows (yeah, I got a little carried away with the coloring...), these seasons cluster toward younger players. Almost two-thirds (64.8%) of all 160+ OPS+ seasons occur when the hitter is age 29 or younger.
A side issue that might be of interest is whether there are times when there are more "older hitters" in the mix of "superstar seasons." That might tell us something about artificial aging patterns over the past 15-20 with regards to the still-raging 'roids issue. There were more of these players in the first decade of the 21st century than at any other time in baseball, so it's a topic that will deserve some additional scrutiny. We'll get back to that in a later post.
Out of a total of 248 hitters with at least one "superstar season," 86 of them are in the Hall of Fame. (Of course, there are many hitters in the Hall who didn't have such a season--mostly players at the left end of the defensive spectrum.)
As is often the case with Hall of Fame voting, the further down we go from "quantity of peak", the murkier things get in terms of who's in and who's out.
Likewise, Pete Browning and Harry Stovey, the two dominant hitters in the 1880s, have their cases strengthened considerably via the lens of "superstar seasons."
A bit under 40% of those with three to five such seasons have been enshrined.
This is just one lens for examining the achievement of hitters, but again it helps delineate where the grey areas in Hall of Fame voting tend to cluster.