According to the ultra reliable resource of Urban Dictionary, normcore is defined as "an exercise in irony. It's being cool through not being cool". It's an anti-trend by nature; the act of standing out in a crowd by dressing absurdly normal. This ultra-conformist fashion movement follows an equally routine progression of trends. In fact, many decade-defining trends are nothing more than counter-culture's active rejection of the ordinary. All trends follow the same fate: a reaction, later commodified, followed by imminent rejection and replacement. The 70's are characterized by the hippie movement, whose fashion and lifestyle functioned as a direct response to 50's and 60's consumer culture. In more recent years, grunge ironically emerged among the youth of the 90's during one of the most profitable eras in American history. Teens rejected the "greed is good" mantra that drove the decade, and dressed accordingly.
Personally, I secretly love normcore. It's easy, comfortable, and refreshing among trends that were beginning to feel stale. Will normcore come to define our current decade? Only time will tell However, if one thing's for sure, the perpetual battle against normalcy will never cease in driving future trend-setters.