Reasonably. Without any specific knowledge, Spotify doesn't actually own the rights to music - it's the rights holders (labels) that chose to make their music available to Spotify under the terms they want.

It's 10 years old at this point, but Sony's leaked contract with Spotify basically outlines that there's no such thing as a 'per stream' rate. Roughly, all the money available was split between the labels (with most favored nation clauses to get them even more money) https://www.theverge.com/2015/5/19/8621581/sony-music-spotif...

Also:

> Contrary to what you might have heard, Spotify does not pay artist royalties according to a per-play or per-stream rate; the royalty payments that artists receive might vary according to differences in how their music is streamed or the agreements they have with labels or distributors.

> In many cases, royalty payments happen once a month, but exactly when and how much artists and songwriters get paid depends on their agreements with their record label or distributor

https://support.spotify.com/us/artists/article/royalties/

Yes, the rates vary by platform. In the US, there's a combo of statutory (or CRB-approved) rates on the publisher side, and negotiations on the label side.

On the publisher/songwriter side, streams are not "public performances" under the Copyright Act (in the US), so royalties are not handled by the court-sanctioned monopolies that have been in place since the early 20th century (ASCAP, BMI).