just that you can not extract more from any streaming source than is there
I don't really see how this would be different from an amp, a speaker or a turntable. Do you think those can extract more than there is in the source?
And funnily enough, streamers and dacs may be the one thing that can easiest improve the source quality by using technologies like the Chord Hugo M Scaler does. We can discuss if it sounds better or not but it tries to make the output sound better than the input.