I'd expect that to be a non-trivial, not-automatable business critical task that requires lots of bodies.
From my brief but traumatising stints working with companies dealing with music, yes, it is a clusterfuck of nonsense that requires industry knowledge, contacts, etc. and only parts of it are amenable to automation (not the important bits, either.)
That happens via a bunch of intermediary aggregators/distributors and a decent part of this automated/automatable.
As I understand it a lot of the staffing overhead at Spotify is in product and marketing - and R&D efforts for retention/acquisition. It also seems like these were a lot of the folk laid off which then impacts growth/retention.
I think you have a very simplistic view of how businesses work since your comparison is not even wrong.
Offices in many countries, licensing, marketing, sales, growth, data, design, engineering all adds up quickly.
There's also a lot of scaling into new markets they didn't have presence in 2014 (which requires scaling in billing, legal, accounting, etc.).