Today's college students are woefully undereducated on the classics.
Asking a 19 year old about a band that peaked 30 years ago seems like a poor metric
Agreed. But at the same time, they are exposed at home, at school and in public (dance clubs, supermarkets, FM, etc) to old (to them) songs. So I think it's one way to see if a song has had lasting power.
Play these 1970s #1s to 1000 college students and see how many recognize them:
"Raindrops Keep Fallin' On My Head"
"Bridge Over Troubled Water"
"Let It Be"
"You've Got a Friend"
"American Pie"
"Lean On Me"
"I Can See Clearly Now"
"Sunshine on My Shoulders"
"Cat's in the Cradle"
"Play That Funky Music"
"Dancing Queen"
"Stayin' Alive"
"My Sharona"
"Escape (The Piña Colada Song)"
I bet more than 2/3rds of them recognize every song
Then play these #1s:
"Everything Is Beautiful"
"I Think I Love You"
"One Bad Apple"
"Indian Reservation"
"Go Away Little Girl"
"Gypsys, Tramps & Thieves"
"Baby, Don't Get Hooked on Me"
"The Night the Lights Went Out in Georgia"
"Show and Tell"
"He Don't Love You (Like I Love You)"
"You Don't Have to Be a Star (To Be in My Show)"
"Undercover Angel"
"MacArthur Park"
They were just as popular in their prime, but I think most college kids would only know a couple, if that.
So it's a metric in one way, but not a sole and perfect measuring stick.
And often this gets thrown off as soon as an old song ends up in the new commercial, like Pet Shop Boys "Opportunities" for example. It goes from largely forgotten (mainstream world/today's 20 year olds, not to music aficionados like us) to everyone suddenly knows it.