Lol, its a common cord progression, perhaps it inspired Stairway, but it surely isn't the same song.
There are only 7 cords, if bands wanted to, they could find all kinds of riffs that sound the same as their song.
It doesn't make it plagiarism.
Tens of thousands of songs have the exact same cord progressions, you cant tell because the words are different and the style is completely different.
The song came out in 71, kind of odd they waited 43 years to sue.
I listened a few times, it sounds a heck of a lot like pink floyd too
this riff in the middle of "is there anybody out there"
Pink Floyd - Is There Anybody Out There? - YouTube
Actually, if you take parts of both riffs, it becomes a lot more of the Taurus song, but its still missing a lot of in between guitar parts that Taurus has in theirs.
Which is why it reminded me of pink floyd as well, some of those parts are in the Floyd song.
If this is plagiarism, then almost every single band is guilty of it.