‘Now and Then’ is the new Beatles song billed as their last ever, but evolving technology makes us wonder what may come in the future — Paul McCartney, 81, and Ringo Starr, 83, are older than my parents. But I’ve played “Now and Then,” the newest and last Beatles song, over and over. It’s like we’re teenagers again. It’s so much more than the music: It’s seeing their lives (and ours) flash before our eyes.