Well it wasnt JUST wins, ERA, strikeouts, walks was still a consideration as well.
Now there is a dozen more stats.
I'm not saying people
only used wins and losses, but they used to be given weight in cy young voting. I remember people arguing against guys like Felix Hernandez didn't deserve as much consideration for the award as he would get because his record was often around .500 mostly because the Mariners usually weren't great. Ironically the year he led the league in wins he finished second in AL CY voting because Zack Greinke pitched out of his mind.
Thankfully in the last 15 years or so things seem to have smartened up and voters recognize that W-L for pitchers is heavily dependent on stuff that happens when the pitcher isn't even on the field and therefore might not be the best yardstick to evaluate whether or not a guy is good. Sure, better pitchers will more often than not have a better chance to win games, but the amount of times that it might not is significant enough that you're better off using almost any other stat (including ERA or Ks and BBs) if you have to pick something to be your north star.
Just as a look at the history of wins being feted for their value by bad sportswriters, here's a small collection of posts on classic site Fire Joe Morgan in which the infatuation with wins of the time (the late 2000s) was taken to task.
www.firejoemorgan.com