Why no "instrumental version" of Katy Perry songs

[GTAmissions1]

Why doesn't Spotify have any songs that are "instrumental" like The One That Got Away or Part of Me by Katy Perry as an example. Is it due to those sountracks not being "offical releases" or does Spotify not have a license to have those soundtracks?

On another question, how do I import songs from iTunes to Spotify consdiering that since not all songs I can find online are on Spotify which iTunes has some of the sountracks that I would like to have on Spotify, but are not yet avalible.