Songshift could allow users to add their own API keys to allow transfers at their own risk.

...and spotify would then sue SongShift. Because why not? Even if you can empirically prove that SongShift is in the right and the API keys belong to the end users, Spotify would only need to litigate long enough for SongShift to give in, settle and disable such a feature again. That's how this game works.

Anti-SLAPP is a thing. https://en.wikipedia.org/wiki/Strategic_lawsuit_against_publ...

Not everywhere.

I mean, wouldn't this worldview imply that literally any company with cash will be able to cause any company with less cash to do whatever they wanted?

The golden rule: he who has the gold makes the rules.

Looks like not old saved tracks so no bulk export.