The piece says that Petty and Lynne "noticed a likeness" between Smith's "Stay With Me" and Petty/Lynne's "I Won't Back Down."
If there's a likeness, it must take the original songwriters to detect it. I guess if I strain really hard I can detect a very slight melodic resemblance in the chorus. But I do have to strain really hard. Otherwise, it's one really good song from circa 1990 and one completely unremarkable tune from ... well, some time recently, I guess. But just because it's completely unremarkable doesn't mean he owes royalties to the authors of a song it bears almost no discernible resemblance to even if the whole idea of "intellectual property" wasn't complete bullshit.
What do you think?