Eventually the ages will just be referred to by their decades. The 30s, the 40s, etc. This has been mentioned many, many times as the de facto quick reference for dealers and hobbyists, and it's just a matter of time before it takes hold as the proper vernacular.
Even after all these years there are people in this hobby that do not acknowledge the Copper Age and think the Modern Age extends all the way back to 1983.
If someone says, "I am interested in selling a collection. It's mostly Modern." That could mean anything. If they say, "It's mostly 90s and early 2000s" then it's much clearer.