[jlarocco]

I don't see how that changes anything.

Post the single with a "Available to buy on <some date>" notice. When it's officially released, take down the notice and put up "Buy now" buttons. And there's no reason they have to make every song available for sale or every song that's for sale available for streaming.

[tomaskafka]

Even better, either 'Let me know when it's available' or 'Auto-buy and add to my collection when it's out'.