Pike or Pipe?

Sayings have a way of morphing over time, especially when the reason or essence of the saying is no longer easily understandable.  Such is the case with "down the pike."  Lately, I'd been hearing people say "down the pipe," which, at first blush, seems to make sense if you're talking about flushing something.  However, the real saying is "down the pike," referring to turnpikes.  I was curious enough about the change in the saying that I Googled it and found that others have been asking the same question.  Pacified, I decided that I wasn't as geeky as I thought I was.  Others itch to find the answers to life's small and peculiar dilemmas, too.  It doesn't really matter if you say "down the pike" or "down the pipe," but at least I've satisfied yet another of the many things that make like "curiouser and curiouser" to me!