I believe this is a no-brainer, outperforming human curation of playlists should already be happening today.
You already have two key things ML requires: lots of data and the user feedback (skipping songs, liking songs, search, etc.. ) which allows ML to learn and create personalized playlists.
Human curation will become obsolete because of such personalization which happens in so many domains. Humans will simply not curate playlists anymore because music listeners will expect such personalized playlists.
I can only sense a lack of priority as the reason why this is not already here today.
Will this make music editors obsolete? Yes in terms of composing playlists.
It would be great if these music editors would focus more on helping listeners to discover the many hidden musical gems out there.
Today, a hit song is more marked by the marketing power behind it then by the sheer talent of the artist. Helping people to discover the hidden talent and look further than the Billboard Hot 100 is to me the real area where music editors can use their passion for music and make a big difference.
That could lead to a great man-machine symbiosis which can only be enriching for the world of music and its inhabitants.