I don’t know, there have been a lot of great guitarists.
I think Marr may still be able to deliver if inspired by a frontman with a vision, that only really happened once after The Smiths and that was with his playing with The The, Matt Johnson brought something out of Johnny that was never heard before. And I actually saw Marr on the Mind Bomb tour in 1990 which was nothing less than amazing. With some exceptions here and there, I don’t really hear him bringing anything new to the table since. Which is fine, he seems to be doing what he wants to do.
Of course some will say the same for Morrissey after Maladusted or Quarry probably. But Morrissey will always inspire, he has such a unique voice and view point that many will always love and some always hate.
Which is more than you can say for other musical acts that are trying and failing to pass themselves off as artists. Rush to danger? They would if they could.