I have compared the two songs at hand (Taurus and Stairway To Heaven), and I do agree that there are similarities, but I also don't think those similarities are all that remarkable - perhaps the initial chord progression and "feel" of Taurus was inspirational for the hit song, either consciously or subconsciously. But I am not a lawyer nor a judge, and not a copyright expert, so I cannot comment on how valid the lawsuit may or may not be. I do think bringing about the lawsuit 45 years or whatever after initial release seems like a stretch...
But it does raise a question that an aspiring (and still lousy) songwriter like me might have:
I listen to lots of music. (Duh.) If I write a song, it is undoubtedly inspired or influenced at some level by the songs I have already heard and maybe even play/sing. How can I ever be sure that I didn't steal the chord progression from one song, a portion of the melody of the verse from another song, the melody of the chorus from a third song, an interesting phrase from a fourth, etc? I might not do it intentionally or consciously, but I'm sure most defendants in such cases (Sam Smith and Petty/Lynne for example) will say something like "I had no intention of stealing that" and "the rest of the song is so different".
In other cases like The Flaming Lips and Cat Stevens, the influence was intentional and they thought they could get away with it. So that is not the situation I am worried about.
Is there some magic algorithm analysis machine at major labels that can compare a song with the existing catalog? (I keed, I keed, I think.)
How do you folks stay out of this copyright trouble? Or is it a case that 90% of songs out there will have a portion that "sounds just like" some other previous, possibly more obscure, song, but they don't get litigated in general because the whole industry would collapse into a massive internecine war of lawsuits?