Those are good reasons for suspicion, but not evidence of wrongdoing that rises to the level of being lawsuit worthy, much less reason for finding in favor of the estate. It’s also highly suspicious that despite Randy Wolfe supposedly thinking a few notes were copied, he never thought it was worth pursuing as a lawsuit.
And what if Wolfe copied Bach or Giovanni Battista Granata first? You can’t copyright public domain music so you also couldn’t violate copyright law by copying a sequence of notes that are in the public domain. While prior art is a term relating to patent law rather than copyright law, it seems like the prior art provided from hundreds of years before makes the claim dubious.
And if you apply the four factor test, you shouldn’t conclude copyright violation even if Page actually did copy the notes anyway. The notes weren’t a large part of Taurus. It’s about 8 seconds of a 2 minute 39 second song that sounds slightly similar (though Taurus sounds like someone trying to play Stairway but can’t remember exactly how to play it - it’s not impressive finger work). Stairway as a whole is substantially different than Taurus. Taurus is instrumental, Stairway isn’t. The guitar solo in question is at the beginning of Stairway and the similar part in Taurus is about 58 seconds in. Stairway has significantly different instrumentation through its very long play time versus a short and monotonous Taurus. Stairway doesn’t affect the potential market for Taurus because they’re significantly different songs. If the notes were copied, the use would be highly transformative.
Edit: Yeah, this - https://www.theguardian.com/music/2016/jun/17/music-expert-testifies-stairway-to-heaven-led-zeppelin-trial
