This is step one in a larger plan that only makes sense when part 3 is announced.
Apple yesterday added Sonos Play1 and Play5 to their stores. Why? Most likely, because they need speakers to sell Apple Music subscriptions. Why not their own rumored system, cause they are a way's off, or they shelved that project. Why not the Play3... cause it's the old model in the line? perhaps going to be changed soon?