When Greg Maddux left Chicago after the 1992 season, he proceeded to put up eleven straight years of winning at least 15 games or more for the Atlanta Braves.
Eleven years. Kerry Wood never reached that mark in any season. In fact, all told, Wood, Mark Prior (1), Matt Clement (0), and Carlos Zambrano (3) only managed the feat four times between them over the course of their careers.
In that eleven year stretch from 1993 to 2003, the Braves had pitchers reach at least 15 wins in a season 29 times.
That's as many times as Cubs pitchers won at least 15 games in the forty-one year period between 1975 and 2015 and Greg Maddux, himself, had by far the most of any Cubs pitcher, accounting for six of those twenty-nine seasons. (The others: Rick Sutcliffe (3); Carlos Zambrano (3); Ted Lilly (2); Ryan Dempster (2); Rick Reuschel (2); Ray Burris (2); Jon Lieber (1); Mike Bielecki (1); Mike Morgan (1); Greg Hibbard (1); Jaime Navarro (1); Steve Trachsel (1); Kevin Tapani (1); Mark Prior (1); and Jake Arrieta (1)).
On Monday, Kyle Hendricks won his fifteenth game of the season. On Tuesday, Jason Hammel fell short of winning his fifteenth and remains stuck on fourteen, having lost his last two starts. Jake Arrieta will go for his eighteenth win of the year on Saturday and Jon Lester won his seventeenth tonight.
The Cubs haven't had three starters with at least 15 wins in a season since 1989 (Greg Maddux 19; Mike Bielecki 18; and Rick Sutcliffe 16).
If Jason Hammel can notch one more win this season, it will be the first time the Cubs have had four pitchers with each more than fifteen wins since 1935 (Lon Warneke 20; Bill Lee 20; Larry French 17; and Charlie Root 15).
What is exemplary for Cubs fans is mundane for Braves fans. In 1998, Atlanta had five pitchers with at least fifteen wins (Tom Glavine 20; Greg Maddux 18; Kevin Millwood 17; John Smoltz 17; and Denny Neagle 16). With John Lackey at nine wins and at most three more starts before the end of the regular season, the Cubs won't challenge those numbers.
Regardless, what they are doing, even if not to the standards of other clubs is virtually unprecedented in the modern history of the franchise.