In most big web services, actual functionality in the API normally seems to leads to its eventual deprecation. Will be interesting to see how this one plays out.
Oh, apparently they're completely blocking access now, yay.
7 years to go from announcing the deprecation to actually removing it seems fair to me. Miles difference from what I'd expect any other company to do (looking at you Google, who seem to announce a deprecation and go through with it in the very same month).
With some caveats though as I mentioned in another comment. Their API for controlling playback doesn't work well with Sonos players for example.