Didn't Justin Vernon say pretty much the same thing in 2012 regarding Bon Iver? Oh, wait; he did:
"[We're] winding it down. I look at it like a faucet. I have to turn it off and walk away from it because so much of how that music comes together is subconscious or discovering. There’s so much attention on the band, it can be distracting at times. I really feel the need to walk away from it while I still care about it. And then if I come back to it – if at all – I'll feel better about it and be renewed or something to do that."
Boom, new music about two years later (I realize its only one song for a soundtrack).
Of course, different artists won't all behave the same, but musicians - especially collaborative musicians - seem to take breaks like this from time to time.