In the thread, which began as a feature request for the Spotify SDK to support tvOS, Erdtman eventually closed out the comments saying that building support for Spotify on Apple TV has been "down prioritized." That might not be an official confirmation that Spotify will never arrive on Apple's set-top box, but Erdtman's wording hints that it's far from Spotify's top priority at the moment.
To support tvOS has been down prioritized, You should not expect a release supporting it any time soon. I'm sorry about that.Although Spotify users might like to take advantage of a tvOS app for Spotify, it's not entirely surprising that the two companies may never reach an agreement on how such an experience would work. Over the summer, Spotify and Apple quarreled over the 30 percent cut that Apple now takes from iOS App Store subscriptions, which has caused Spotify to charge $12.99 for subscriptions purchased through the App Store, a $3 premium over subscriptions purchased on the web and $3 more than the price of Apple Music.
Spotify claimed Apple was using such a tactic as a "weapon to harm competitors," while Apple accused Spotify of "resorting to rumors and half-truths" to gain public opinion in its favor. Apple's new music royalty proposal for streaming services also adversely affects the free tiers of companies like Spotify and YouTube.
A potential Spotify tvOS app would likely be a free download users could use as a companion app to stream their music, but with so much bad blood between the two companies, it still seems likely that Spotify will simply avoid creating an app for tvOS at all. Amazon is also refraining from launching an Amazon Prime Video app on Apple TV, reportedly until Apple presents it with "acceptable business terms."
For Spotify users frustrated with the news, Apple's AirPlay feature can still be used to stream music from Spotify on an iPhone or iPad through a connected Apple TV.
Update: As several readers have pointed out, Erdtman's comment pertains specifically to the SDK that allows third-party developers to incorporate Spotify functionality into their apps. Spotify is apparently not prioritizing Apple TV support for that SDK, but that does not necessarily mean the company has no plans for an Apple TV app of its own.