Even with licensing costs at zero, the infra of Youtube, the closest thing to Spotify for video, is a very different beast. And I'd argue youtube doesn't go far enough.
So, while you are right that video streaming is much more costly than audio streaming, I think GP is overall more correct about the reasoning being production costs rather than anything to do with distribution.
Reduced hot-storage, increased playlist. Sort of media communism but the capitalists still hold the keys?