When actor Luke Perry, best known for portraying TV heartthrob Dylan McKay on the ’90s teen drama “Beverly Hills, 90210,” died Monday after suffering a massive stroke, there were the usual public displays of sadness when a public figure leaves us. But his passing was especially painful for people of a certain age. As one fan expressed on Twitter: “I’m in mourning for Generation X today, for real.” Perry died at just 52 years old. Which makes him the first Gen X icon to succumb to natural causes. That’s an unsettling reality check to those of us who identify as...