The artist questions, and answers it. When it's time to leave, does he want to remember the 70s--his 70s? Do any of us--our 70s? We can have 70s that aren't in that decade, the "killing time" years. I had a few; they were probably in the mid-oughts.
We can let them go; they don't matter any more aside from what they might've forged or made fall away.