"Best guitarist" lists are always controversial.
Here's a short list of who got left out of the Rolling Stone list cited above, that put GL at 47-
Roy Buchanan, Danny Gatton, Michael Schenker, Alvin Lee, Warren Haynes, Joe Satriani, Steve Vai, Sonny Landreth, Robin Trower, Gary Moore, Rick Derringer, Steve Howe, Eric Johnson, John Fogerty, Joe Bonamassa, Steve Morse, Steve Lukather, Jorma Kaukonen, Guthrie Govan, Brian Setzer, Tommy Emmanuel, Lenny Breau, and Hank Marvin.
They also tend to put in people for their accomplishments rather than ability and technique.
I frequently see Pete Townsend and Jerry Garcia in "best guitarist" lists.
Neither was anywhere near as good as the list I posted of "left out", but they always seem to make it in.