Youtubers themselves were screaming about this recently, and almost always with any algo/payout change, and that is pre-Youtube red renegotiations.
I've never really used SoundCloud because the ui is confusing and haphazard and it just doesn't feel like Spotify, which I pay for. Spotify makes sure and shows you the album art etc. My recollection of SoundCloud from when I tried it in the past was some sort of waveform you clicked on to listen and visualize the music.
Soundcloud was more of an independent artist platform, and I think Soundcloud might have been able to get artists to pay for some services like sponsored songs, pay to let users download their tracks, artist page perks.
But it's hard to know if that would have worked. Especially in retrospect.
(1) Video content engages a wider audience and commands more focus than audio content
(2) Video advertisements dropped into video content are more effective than audio advertisements.
But that's a guess with no empirical base.