An Apple spokesperson, in a statement to John Gruber:

We can’t wait for people to experience HomePod, Apple’s breakthrough wireless speaker for the home, but we need a little more time before it’s ready for our customers. We’ll start shipping in the US, UK and Australia in early 2018.

This is awfully disappointing. Especially after the AirPods’ supply issues last year. Maybe Apple should reconsider whether they should be announcing new products so early.