I buy books (physical or electronic) with the express intent of reading them now, or very, very
soon. It doesn't always work out that way, but I don't usually buy books for a rainy day/the future/or retirement ... whatever the heck
that is.
My TBR pile is, in fact, primarily virtual. The books I've purchased that I haven't gotten around to reading yet, run a very real risk of never being read. I'm OK with this.