Dan,

I think what struck me about The Ballroom Thieves song is that it is about the passage of time and the wonderment of where it all went and how so fast. 

Lately, in music, this is the theme in songs that has struck me - that when we get to a sudden age we wonder what has just happened. 

It's the theme that has been present in Mellencamp's and Springsteen's duet Wasted Days, Sean Rowe's I'll Follow Your Trail, William Wild's Holy Ghost, Neil Young's It's A Dream, and Ceramic Animal's Sweet Unknown. 

Also, to me, it's about the lamentation of that past time and hopefully, if we are lucky,  rather than weeping over the short time that is left, we try and find a better way to accept our more pressingly discovered mortality and that it is coming quicker and quicker and how to enjoy the future unknown as well as the past known.