It really isn't that shocking a statement. He's a rock icon of the 21st century. Lyrically excellent, creates a recognisable sound with his guitar that you instantly associate with him and has a unique and iconic voice. Just cause he hasn't died or had 20 years for his sound to be played to death on Radio 2 doesn't mean he isn't up there with them.
It's like the debate of Messi vs Maradona.
What are you going to judge him on though? Record sales? Creed have sold more records than Hendrix so thats out the window.
Name me someone of his era that is as iconic to rock as he is, that writes his own music, plays his own instrument and writes his own lyrics and has done for more than a decade now while being involved in a number of projects. He's a true musician.
He's not going to pioneer the electric guitar like Henrix could because he was born in the wrong decade, he's not going to be a pure rock icon in the way Presley could because it's such a diluted industry now and he's not going to grab the fascination of the media like Dylan because the media aren't interested in intellect any more, they're interested in Rhianna and Will-i-am.
He's a huge talent and will still be knocking out classics in 20 years if he's alive. If he's dead, he'll be even bigger.